Journal articles: 'Maximal voluntary ventilation'

1

Heliopoulos, Ioannis, Georgios Patlakas, Kostantinos Vadikolias, Nicolaos Artemis, Kleopas A. Kleopa, Eustratios Maltezos, and Haritomeni Piperidou. "Maximal voluntary ventilation in myasthenia gravis." Muscle & Nerve 27, no. 6 (May 19, 2003): 715–19. http://dx.doi.org/10.1002/mus.10378.

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Smith, Janette L., Jane E. Butler, Peter G. Martin, Rachel A. McBain, and Janet L. Taylor. "Increased ventilation does not impair maximal voluntary contractions of the elbow flexors." Journal of Applied Physiology 104, no. 6 (June 2008): 1674–82. http://dx.doi.org/10.1152/japplphysiol.01358.2007.

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Exercise performance is impaired by increased respiratory work, yet the mechanism for this is unclear. This experiment assessed whether neural drive to an exercising muscle was affected by cortically driven increases in ventilation. On each of 5 days, eight subjects completed a 2-min maximal voluntary contraction (MVC) of the elbow flexor muscles, followed by 4 min of recovery, while transcranial magnetic stimulation tested for suboptimal neural drive to the muscle. On 1 day, subjects breathed without instructions under normocapnia. During the 2-min MVC, ventilation was ∼3.5 times that at rest. On another day, subjects breathed without instruction under hypercapnia. During the 2-min MVC, ventilation was ∼1.5 times that on the normocapnic day. On another 2 days under normocapnia, subjects voluntarily matched their breathing to the uninstructed breathing under normocapnia and hypercapnia using target feedback of the rate and inspiratory volume. On a fifth day under normocapnia, the volume feedback was set to each subject's vital capacity. On this day, ventilation during the 2-min MVC was approximately twice that on the uninstructed normocapnic day (or ∼7 times rest). The experimental manipulations succeeded in producing voluntary and involuntary hyperpnea. However, maximal voluntary force, fatigue and voluntary activation of the elbow flexor muscles were unaffected by cortically or chemically driven increases in ventilation. Results suggest that any effects of increased respiratory work on limb exercise performance are not due to a failure to drive both muscle groups optimally.

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Haverkamp, Hans C., Adriane Morrison-Taylor, Jeni Demar, Andrew Klansky, Kasie Craig, and Eden Towers. "Effect Of Daily, High-intensity Voluntary Hyperpnea On Maximal Expired Airflow And Maximal Voluntary Ventilation." Medicine & Science in Sports & Exercise 50, no. 5S (May 2018): 123. http://dx.doi.org/10.1249/01.mss.0000535491.21087.4d.

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Milic-Emili, Joseph, and Marcello M. Orzalesi. "Mechanical work of breathing during maximal voluntary ventilation." Journal of Applied Physiology 85, no. 1 (July 1, 1998): 254–58. http://dx.doi.org/10.1152/jappl.1998.85.1.254.

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With the use of the esophageal balloon technique, the working capacity of the respiratory muscles was assessed in four normal subjects by measuring the work per breath (W) and respiratory power (W˙) during maximal voluntary ventilation with imposed respiratory frequencies (f) ranging from 20 to 273 cycles/min. Measurements were made in a body plethysmograph to assess the work wasted as a result of alveolar gas compressibility (Wg′). In line with other types of human voluntary muscle activity, W decreased with increasing f, whereasW˙ exhibited a maximum at f of ∼100 cycles/min. Up to this f value, Wg′ was small relative to W. With further increase in f, the Wg′/W ratio increased progressively, amounting to 8–22% of W˙ at f of 200 cycles/min.

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Mulvey, D. A., N. G. Koulouris, M. W. Elliott, C. M. Laroche, J. Moxham, and M. Green. "Inspiratory muscle relaxation rate after voluntary maximal isocapnic ventilation in humans." Journal of Applied Physiology 70, no. 5 (May 1, 1991): 2173–80. http://dx.doi.org/10.1152/jappl.1991.70.5.2173.

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We have investigated whether the capacity of the inspiratory muscles to generate pressure and flow during a ventilatory load is related to changes in inspiratory muscle relaxation rate. Five highly motivated normal subjects performed voluntary maximal isocapnic ventilation (MIV) for 2 min. Minute ventilation and esophageal, gastric, and transdiaphragmatic pressures were measured breath by breath. We observed that ventilation, peak inspiratory and expiratory pressures, and inspiratory flow rate declined from the start of the run to reach a plateau at 60 s that was sustained for the remainder of the exercise. In a subsequent series of studies, MIV was performed for variable durations between 15 and 120 s. The normalized maximum relaxation rate of unoccluded inspiratory sniffs (sniff MRR, %pressure loss/10 ms) was determined immediately on stopping MIV. Sniff MRR slowed as the duration of MIV increased and paralleled the decline in inspiratory pressure and ventilation observed during the 2-min exercise. No further slowing in MRR occurred when ventilation became sustainable. We conclude that, during MIV, the progressive loss of ventilation and capacity to generate pressure is associated with the early onset and progression of a peripheral fatiguing process within the inspiratory muscles.

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Suh, Mi Ri, Dong Hyun Kim, Jiho Jung, Bitnarae Kim, Jang Woo Lee, Won Ah Choi, and Seong-Woong Kang. "Clinical implication of maximal voluntary ventilation in myotonic muscular dystrophy." Medicine 98, no. 18 (May 2019): e15321. http://dx.doi.org/10.1097/md.0000000000015321.

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Stein, Richard, Hiran Selvadurai, Allan Coates, Donna L. Wilkes, Jane Schneiderman-Walker, and Mary Corey. "Determination of maximal voluntary ventilation in children with cystic fibrosis." Pediatric Pulmonology 35, no. 6 (May 8, 2003): 467–71. http://dx.doi.org/10.1002/ppul.10298.

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Silva, Jaksoel C., Ideza E. Carvalho, Simone Dal Corso, and Fernanda C. Lanza. "Reference equation for maximal voluntary ventilation in children and adolescents." Pediatric Pulmonology 55, no. 2 (November 19, 2019): 426–32. http://dx.doi.org/10.1002/ppul.24576.

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9

Suh, Miri, Bitnarae Kim, Won-Ah Choi, and Seong-Woong Kang. "Clinical Implication of Maximal Voluntary Ventilation in Myotonic Muscular Dystrophy." Chest 150, no. 4 (October 2016): 1124A. http://dx.doi.org/10.1016/j.chest.2016.08.1233.

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10

Anholm, J. D., J. Stray-Gundersen, M. Ramanathan, and R. L. Johnson. "Sustained maximal ventilation after endurance exercise in athletes." Journal of Applied Physiology 67, no. 5 (November 1, 1989): 1759–63. http://dx.doi.org/10.1152/jappl.1989.67.5.1759.

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Although impaired respiratory muscle performance that persists up to 5 min after exercise is stopped has been demonstrated during exhaustive exercise in normal young men, it is not known whether impaired respiratory muscle function follows endurance exercise to exhaustion in highly trained athletes. To study the effects of exercise on sustained maximal voluntary ventilation immediately after exercise, eight elite cross-country skiers performed a 4-min maximal sustained ventilation (MSV) test before and immediately after exhaustive exercise. Subjects were encouraged to maintain maximal ventilation (VE) throughout the MSV test. To encourage greater effort, rapid visual feedback of VE was provided on a computer terminal along with a target VE based on their 12-s maximum voluntary ventilation (MVV). The subjects (7 males, 1 female) were 18.5 +/- 0.9 yr old (mean +/- SD) and exercised for 62.5 +/- 16.7 min at 77 +/- 5% of their maximum oxygen consumption during which average VE was 106.7 +/- 24.2 l/min BTPS. The mean MVV was 196.0 +/- 29.9 l/min or 107% of their age- and height-predicted MVV. Before exercise the MSV was 86% of the MVV or 176.7 +/- 30.5 l/min, whereas after exercise the MSV was 90% of the MVV or 180.3 +/- 28.9 l/min (P = NS). The total volume of gas expired during the 4-min MSV was 706.7 +/- 121.9 liters before and 721.2 +/- 115.5 liters after exercise (P = NS). In this group of athletes, exhaustive exercise produced no deleterious effects on the ability to perform a 4-min MSV test immediately after exercise.

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Razi, Salman S., William G. Petersen, Mary Yaktus, and Mark W. Riggs. "Correlation of Spirometric Values With the Measured Maximal Voluntary Ventilation (MVV." Chest 124, no. 4 (January 2003): 122S. http://dx.doi.org/10.1378/chest.124.4_meetingabstracts.122s-b.

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12

Polkey, M. I., D. Kyroussis, C. H. Hamnegard, G. H. Mills, P. D. Hughes, M. Green, and J. Moxham. "Diaphragm performance during maximal voluntary ventilation in chronic obstructive pulmonary disease." American Journal of Respiratory and Critical Care Medicine 155, no. 2 (February 1997): 642–48. http://dx.doi.org/10.1164/ajrccm.155.2.9032207.

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13

Kor, Ai Ching, Kian Chung Ong, Arul Earnest, and Yee Tang Wang. "Prediction of the maximal voluntary ventilation in healthy adult Chinese subjects." Respirology 9, no. 1 (March 2004): 76–80. http://dx.doi.org/10.1111/j.1440-1843.2003.00532.x.

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14

Keeling, William F., and Bruce J. Martin. "Supine Position and Sleep Loss Each Reduce Prolonged Maximal Voluntary Ventilation." Respiration 54, no. 2 (1988): 119–26. http://dx.doi.org/10.1159/000195511.

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15

Nunn, John F., and Srinivasa N. Raja. "Conscious Volunteers Developed Hypoxemia and Pulmonary Collapse When Breathing Air and Oxygen at Reduced Lung Volume." Anesthesiology 98, no. 1 (January 1, 2003): 258–59. http://dx.doi.org/10.1097/00000542-200301000-00037.

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Ventilation at maximal voluntary reduction of lung volume caused significant desaturation in some healthy subjects breathing air. Saturation rapidly returned to control levels when normal lung volume was regained. These changes are probably due to reversible airway obstruction. During the inhalation of oxygen, ventilation at maximal voluntary reduction of lung volume caused, in one subject, a reduction of arterial Po2 of 243 mmHg. Normal arterial Po2 was not immediately restored on regaining normal lung volume. Chest radiographs showed extensive atelectasis, which persisted for several hours in an ambulant subject. These changes are probably due to absorption of oxygen from alveoli beyond obstructed airways. Reduction of lung volume may be harmful for patients who are breathing oxygen. Caution is therefore necessary in the use of a subatmospheric pressure phase during artificial ventilation and during suction of the tracheobronchial tree.

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16

Lira, Claudio Andre Barbosa de, Fabio Carderelli Minozzo, Bolivar Saldanha Sousa, Rodrigo Luiz Vancini, Marilia dos Santos Andrade, Abrahao Augusto Juviniano Quadros, Acary Souza Bulle Oliveira, and Antonio Carlos da Silva. "Lung function in post-poliomyelitis syndrome: a cross-sectional study." Jornal Brasileiro de Pneumologia 39, no. 4 (June 2013): 455–60. http://dx.doi.org/10.1590/s1806-37132013000400009.

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OBJECTIVE: To compare lung function between patients with post-poliomyelitis syndrome and those with sequelae of paralytic poliomyelitis (without any signs or symptoms of post-poliomyelitis syndrome), as well as between patients with post-poliomyelitis syndrome and healthy controls. METHODS: Twenty-nine male participants were assigned to one of three groups: control; poliomyelitis (comprising patients who had had paralytic poliomyelitis but had not developed post-poliomyelitis syndrome); and post-poliomyelitis syndrome. Volunteers underwent lung function measurements (spirometry and respiratory muscle strength assessment). RESULTS: The results of the spirometric assessment revealed no significant differences among the groups except for an approximately 27% lower mean maximal voluntary ventilation in the post-poliomyelitis syndrome group when compared with the control group (p = 0.0127). Nevertheless, the maximal voluntary ventilation values for the post-poliomyelitis group were compared with those for the Brazilian population and were found to be normal. No significant differences were observed in respiratory muscle strength among the groups. CONCLUSIONS: With the exception of lower maximal voluntary ventilation, there was no significant lung function impairment in outpatients diagnosed with post-poliomyelitis syndrome when compared with healthy subjects and with patients with sequelae of poliomyelitis without post-poliomyelitis syndrome. This is an important clinical finding because it shows that patients with post-poliomyelitis syndrome can have preserved lung function.

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Cordeiro, Alexandre Miguel Guerra, Mónica Teixeira, Miguel Faria, Mafalda Sousa, Paulo Serrasqueiro, and Rodrigo Ruivo. "The effect of thoracic manipulation on pulmonary function in swimmers." Revista Andaluza de Medicina del Deporte 14, no. 2 (March 11, 2020): 65–69. http://dx.doi.org/10.33155/j.ramd.2020.03.005.

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Objective: Spinal manipulation has been used to improve respiratory function in healthy individuals. However, it has been observed that there are no studies in the context of sports activities. The objective of this study was to analyse the effect of thoracic spinal manipulation on forced vital capacity, forced expiratory volume in one second and maximal voluntary ventilation in swimmers. Method: A randomized controlled crossover study consisting of 21 swimmers, divided into two groups (Intervention vs Control), aged 16 – 24y, where forced vital capacity, forced expiratory volume in one second and maximal voluntary ventilation were measured in five evaluation moments: at baseline and, 1 minute, 10 minutes, 20 minutes and 30 minutes following the thoracic spinal manipulation procedures. Results: ANOVA tests showed no statistically significant differences for forced vital capacity (p = 0.35) and forced expiratory volume in one second (p = 0.25) among the five evaluation moments. With the maximal voluntary ventilation there was a statistically significant (p = 0.02) reduction, observed between baseline (86.00 litres) and at 10 minutes (79.29 litres) and 30 minutes (76.24 litres). No significant differences were observed between the results of intervention and control groups. Conclusions: In the current study no significant differences were observed in pulmonary function after thoracic spinal manipulation. Future research efforts should examine the effects of different manual therapy techniques and treatment protocols.

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Fulton, J. E., J. M. Pivarnik, A. L. Tate, W. C. Taylor, and S. A. Snider. "1032 ESTIMATION OF MAXIMAL VOLUNTARY VENTILATION (MVV) IN AFRICAN-AMERICAN ADOLESCENT GIRLS." Medicine & Science in Sports & Exercise 25, Supplement (May 1993): S184. http://dx.doi.org/10.1249/00005768-199305001-01035.

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19

Babb, T. G., and J. R. Rodarte. "Estimation of ventilatory capacity during submaximal exercise." Journal of Applied Physiology 74, no. 4 (April 1, 1993): 2016–22. http://dx.doi.org/10.1152/jappl.1993.74.4.2016.

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There is presently no precise way to determine ventilatory capacity for a given individual during exercise; however, this information would be helpful in evaluating ventilatory reserve during exercise. Using schematic representations of maximal expiratory flow-volume curves and individual maximal expiratory flow-volume curves from four subjects, we describe a technique for estimating ventilatory capacity. In these subjects, we measured maximal expiratory flow-volume loops at rest and tidal flow-volume loops and inspiratory capacity (IC) during submaximal cycle ergometry. We also compared minute ventilation (VE) during submaximal exercise with calculated ventilatory maxima (VEmaxCal) and with maximal voluntary ventilation (MVV) to estimate ventilatory reserve. Using the schematic flow-volume curves, we demonstrated the theoretical effect of maximal expiratory flow and lung volume on ventilatory capacity and breathing pattern. In the subjects, we observed that the estimation of ventilatory reserve with use of VE/VEmaxCal was most helpful in indicating when subjects were approaching maximal expiratory flow over a large portion of tidal volume, especially at submaximal exercise levels where VE/VEmaxCal and VE/MVV differed the most. These data suggest that this technique may be useful in estimating ventilatory capacity, which could then be used to evaluate ventilatory reserve during exercise.

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RAFFERTY, GERRARD F, M. LOU HARRIS, MICHAEL I POLKEY, ANNE GREENOUGH, and JOHN MOXHAM. "Effect of Hypercapnia on Maximal Voluntary Ventilation and Diaphragm Fatigue in Normal Humans." American Journal of Respiratory and Critical Care Medicine 160, no. 5 (November 1999): 1567–71. http://dx.doi.org/10.1164/ajrccm.160.5.9801114.

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Neder, J. A., S. Andreoni, M. C. Lerario, and L. E. Nery. "Reference values for lung function tests: II. Maximal respiratory pressures and voluntary ventilation." Brazilian Journal of Medical and Biological Research 32, no. 6 (June 1999): 719–27. http://dx.doi.org/10.1590/s0100-879x1999000600007.

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22

Zareian, Parvin, Farzaneh Ketabjg, and Afrooz Kargarfard. "Prediction of the maximal voluntary ventilation(MVV) in healthy students of school Jahrom medical." Pars of Jahrom University of Medical Sciences 2, no. 2 (April 1, 2005): 12–18. http://dx.doi.org/10.29252/jmj.2.2.4.

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23

Mota, Susana, Pere Casan, Franchek Drobnic, Jordi Giner, Olga Ruiz, Joaquín Sanchis, and Joseph Milic-Emili. "Expiratory flow limitation during exercise in competition cyclists." Journal of Applied Physiology 86, no. 2 (February 1, 1999): 611–16. http://dx.doi.org/10.1152/jappl.1999.86.2.611.

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In some trained athletes, maximal exercise ventilation is believed to be constrained by expiratory flow limitation (FL). Using the negative expiratory pressure method, we assessed whether FL was reached during a progressive maximal exercise test in 10 male competition cyclists. The cyclists reached an average maximal O2 consumption of 72 ml ⋅ kg−1 ⋅ min−1(range: 67–82 ml ⋅ kg−1 ⋅ min−1) and ventilation of 147 l/min (range: 122–180 l/min) (88% of preexercise maximal voluntary ventilation in 15 s). In nine subjects, FL was absent at all levels of exercise (i.e., expiratory flow increased with negative expiratory pressure over the entire tidal volume range). One subject, the oldest in the group, exhibited FL during peak exercise. The group end-expiratory lung volume (EELV) decreased during light-to-moderate exercise by 13% (range: 5–33%) of forced vital capacity but increased as maximal exercise was approached. EELV at peak exercise and at rest were not significantly different. The end-inspiratory lung volume increased progressively throughout the exercise test. The conclusions reached are as follows: 1) most well-trained young cyclists do not reach FL even during maximal exercise, and, hence, mechanical ventilatory constraint does not limit their aerobic exercise capacity, and 2) in absence of FL, EELV decreases initially but increases during heavy exercise.

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Villamor, Gabriela A., Lindsay M. Andras, Greg Redding, Priscella Chan, Joshua Yang, and David L. Skaggs. "A Comparison of Maximal Voluntary Ventilation and Forced Vital Capacity in Adolescent Idiopathic Scoliosis Patients." Spine Deformity 7, no. 5 (September 2019): 729–33. http://dx.doi.org/10.1016/j.jspd.2019.02.007.

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25

Han, Jin-Tae, Min-Ji Go, and Yeong-Ju Kim. "Comparison of Forced Vital Capacity and Maximal Voluntary Ventilation Between Normal and Forward Head Posture." Journal of the Korean Society of Physical Medicine 10, no. 1 (February 28, 2015): 83–89. http://dx.doi.org/10.13066/kspm.2015.10.1.83.

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26

Turner, Louise A., Sandra L. Tecklenburg-Lund, Robert F. Chapman, Joel M. Stager, Daniel P. Wilhite, and Timothy D. Mickleborough. "Inspiratory muscle training lowers the oxygen cost of voluntary hyperpnea." Journal of Applied Physiology 112, no. 1 (January 1, 2012): 127–34. http://dx.doi.org/10.1152/japplphysiol.00954.2011.

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The purpose of this study was to determine if inspiratory muscle training (IMT) alters the oxygen cost of breathing (V̇o2RM) during voluntary hyperpnea. Sixteen male cyclists completed 6 wk of IMT using an inspiratory load of 50% (IMT) or 15% placebo (CON) of maximal inspiratory pressure (Pimax). Prior to training, a maximal incremental cycle ergometer test was performed to determine V̇o2and ventilation (V̇E) at multiple workloads. Pre- and post-training, subjects performed three separate 4-min bouts of voluntary eucapnic hyperpnea (mimic), matching V̇Ethat occurred at 50, 75, and 100% of V̇o2 max. Pimaxwas significantly increased ( P < 0.05) by 22.5 ± 8.7% from pre- to post-IMT and remained unchanged in the CON group. The V̇o2RMrequired during the mimic trial corresponded to 5.1 ± 2.5, 5.7 ± 1.4, and 11.7% ± 2.5% of the total V̇o2(V̇o2T) at ventilatory workloads equivalent to 50, 75, and 100% of V̇o2 max, respectively. Following IMT, the V̇o2RMrequirement significantly decreased ( P < 0.05) by 1.5% (4.2 ± 1.4% of V̇o2T) at 75% V̇o2 maxand 3.4% (8.1 ± 3.5% of V̇o2T) at 100% V̇o2 max. No significant changes were shown in the CON group. IMT significantly reduced the O2cost of voluntary hyperpnea, which suggests that a reduction in the O2requirement of the respiratory muscles following a period of IMT may facilitate increased O2availability to the active muscles during exercise. These data suggest that IMT may reduce the O2cost of ventilation during exercise, providing an insight into mechanism(s) underpinning the reported improvements in whole body endurance performance; however, this awaits further investigation.

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27

Carneiro, A. B. M., N. Zekhry, F. C. Torres, F. A. A. Lauro, M. A. D. Danucalov, Y. Juliano, M. T. Mello, S. Tufik, and A. C. Silva. "BREATHING RESERVE USING ESTIMATED AND MEASURED MAXIMAL VOLUNTARY VENTILATION IN PARALYMPIC ATHLETES WITH CEREBRAL PALSY 478." Medicine &amp Science in Sports &amp Exercise 29, Supplement (May 1997): 83. http://dx.doi.org/10.1097/00005768-199705001-00477.

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KORZAN, SOPHIE, NANCY MCLELLAN, ANIKET SHARMA, TALAL KAISER, and DEBAPRIYA DATTA. "COMPARISON OF BREATHING RESERVE OBTAINED FROM MEASURED AND ESTIMATED MAXIMAL VOLUNTARY VENTILATION IN CARDIOPULMONARY EXERCISE TESTING." Chest 154, no. 4 (October 2018): 970A. http://dx.doi.org/10.1016/j.chest.2018.08.882.

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Gagnon, Philippe, Didier Saey, Isabelle Vivodtzev, Louis Laviolette, Vincent Mainguy, Julie Milot, Steeve Provencher, and François Maltais. "Impact of preinduced quadriceps fatigue on exercise response in chronic obstructive pulmonary disease and healthy subjects." Journal of Applied Physiology 107, no. 3 (September 2009): 832–40. http://dx.doi.org/10.1152/japplphysiol.91546.2008.

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Exercise intolerance in chronic obstructive pulmonary disease (COPD) results from a complex interaction between central (ventilatory) and peripheral (limb muscles) components of exercise limitation. The purpose of this study was to evaluate the influence of quadriceps muscle fatigue on exercise tolerance and ventilatory response during constant-workrate cycling exercise testing (CWT) in patients with COPD and healthy subjects. Fifteen patients with COPD and nine age-matched healthy subjects performed, 7 days apart, two CWTs up to exhaustion at 80% of their predetermined maximal work capacity. In a randomized order, one test was performed with preinduced quadriceps fatigue and the other in a fresh state. Quadriceps fatigue was produced by electrostimulation-induced contractions and quantified by maximal voluntary contraction and potentiated twitch force (TwQpot). Endurance time and ventilatory response during CWT were compared between fatigued and fresh state. Endurance time significantly decreased in the fatigued state compared with the fresh condition in COPD (356 ± 69 s vs. 294 ± 45 s, P < 0.05) and controls (450 ± 74 s vs. 340 ± 45 s, P < 0.05). Controls showed significantly higher ventilation and end-exercise dyspnea scores in the fatigued condition, whereas, in COPD, fatigue did not influence ventilation or dyspnea during exercise. The degree of ventilatory limitation, as expressed by the V̇e/maximum voluntary ventilation ratio, was similar in both conditions in patients with COPD. We conclude that it is possible to induce quadriceps fatigue by local electrostimulation-induced contractions. Our findings demonstrate that peripheral muscle fatigue is an additional important factor, besides intense dyspnea, that limits exercise tolerance in COPD.

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Hu, Shou-Jia, Xue-Ke Zhao, Xin Song, Ling-Ling Lei, Wen-Li Han, Rui-Hua Xu, Ran Wang, Fu-You Zhou, Liang Wang, and Li-Dong Wang. "Preoperative maximal voluntary ventilation, hemoglobin, albumin, lymphocytes and platelets predict postoperative survival in esophageal squamous cell carcinoma." World Journal of Gastroenterology 27, no. 4 (January 28, 2021): 321–35. http://dx.doi.org/10.3748/wjg.v27.i4.321.

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31

Babb, T. G., R. Viggiano, B. Hurley, B. Staats, and J. R. Rodarte. "Effect of mild-to-moderate airflow limitation on exercise capacity." Journal of Applied Physiology 70, no. 1 (January 1, 1991): 223–30. http://dx.doi.org/10.1152/jappl.1991.70.1.223.

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To determine the effect of mild-to-moderate airflow limitation on exercise tolerance and end-expiratory lung volume (EELV), we studied 9 control subjects with normal pulmonary function [forced expired volume in 1 s (FEV1) 105% pred; % of forced vital capacity expired in 1 s (FEV1/FVC%) 81] and 12 patients with mild-to-moderate airflow limitation (FEV1 72% pred; FEV1/FVC % 58) during progressive cycle ergometry. Maximal exercise capacity was reduced in patients [69% of pred maximal O2 uptake (VO2max)] compared with controls (104% pred VO2max, P less than 0.01); however, maximal expired minute ventilation-to-maximum voluntary ventilation ratio and maximal heart rate were not significantly different between controls and patients. Overall, there was a close relationship between VO2max and FEV1 (r2 = 0.62). Resting EELV was similar between controls and patients [53% of total lung capacity (TLC)], but at maximal exercise the controls decreased EELV to 45% of TLC (P less than 0.01), whereas the patients increased EELV to 58% of TLC (P less than 0.05). Overall, EELV was significantly correlated to both VO2max (r = -0.71, P less than 0.001) and FEV1 (r = -0.68, P less than 0.001). This relationship suggests a ventilatory influence on exercise capacity; however, the increased EELV and associated pleural pressures could influence cardiovascular function during exercise. We suggest that the increase in EELV should be considered a response reflective of the effect of airflow limitation on the ventilatory response to exercise.

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32

Haas, F., S. Pasierski, N. Levine, M. Bishop, K. Axen, H. Pineda, and A. Haas. "Effect of aerobic training on forced expiratory airflow in exercising asthmatic humans." Journal of Applied Physiology 63, no. 3 (September 1, 1987): 1230–35. http://dx.doi.org/10.1152/jappl.1987.63.3.1230.

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Pulmonary function after exercise was evaluated in 22 asthmatic subjects before and after a 36-session training sequence of aerobic exercise. Training did not change pulmonary function values, except for a small increase in maximal voluntary ventilation (P less than 0.02), which was attributed to respiratory muscle training. After aerobic training, both external work at a given heart rate and peak O2 consumption increased by 30 and 15%, respectively. At the same minute ventilation (VE), immediate postexercise forced expiratory airflow was higher after training (P less than 0.02), and reduction in forced expiratory airflow during the first 9 min postexercise was less after training (P less than 0.01). The posttraining airflow response to the pretraining work load was, as expected, less than the pretraining response (P less than 0.02). Although the difference in maximal-to-minimal airflow at the same VE was similar before and after training, the airflow increase accounted for 50% of the response after training compared with 16% of the pretraining response. Furthermore the strong negative correlation (P less than 0.01) between maximal and minimal airflow both pre- and posttraining indicates that exercise-induced bronchospasm (EIB) severity is, in part, determined by the degree of exercise-induced bronchodilation. We conclude that aerobic training significantly increases exercise-induced bronchodilation and diminishes EIB.

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Yerg, J. E., D. R. Seals, J. M. Hagberg, and J. O. Holloszy. "Effect of endurance exercise training on ventilatory function in older individuals." Journal of Applied Physiology 58, no. 3 (March 1, 1985): 791–94. http://dx.doi.org/10.1152/jappl.1985.58.3.791.

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To evaluate the effect of endurance training on ventilatory function in older individuals, 1) 14 master athletes (MA) [age 63 +/- 2 yr (mean +/- SD); maximum O2 uptake (VO2max) 52.1 +/- 7.9 ml . kg-1 . min-1] were compared with 14 healthy male sedentary controls (CON) (age 63 +/- 3 yr; VO2max of 27.6 +/- 3.4 ml . kg-1 . min-1), and 2) 11 sedentary healthy men and women, age 63 +/- 2 yr, were reevaluated after 12 mo of endurance training that increased their VO2max 25%. MA had a significantly lower ventilatory response to submaximal exercise at the same O2 uptake (VE/VO2) and greater maximal voluntary ventilation (MVV), maximal exercise ventilation (VEmax), and ratio of VEmax to MVV than CON. Except for MVV, all of these parameters improved significantly in the previously sedentary subjects in response to training. Hypercapnic ventilatory response (HCVR) at rest and the ventilatory equivalent for CO2 (VE/VCO2) during submaximal exercise were similar for MA and CON and unaffected by training. We conclude that the increase in VE/VO2 during submaximal exercise observed with aging can be reversed by endurance training, and that after training, previously sedentary older individuals breathe at the same percentage of MVV during maximal exercise as highly trained athletes of similar age.

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Al-Ani, M., K. Robins, A. H. Al-Khalidi, J. Vaile, J. Townend, and J. H. Coote. "Isometric Contraction of Arm Flexor Muscles as a Method of Evaluating Cardiac Vagal Tone in Man." Clinical Science 92, no. 2 (February 1, 1997): 175–80. http://dx.doi.org/10.1042/cs0920175.

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1. We have previously shown that brief voluntary isometric contractions of upper arm flexor muscles performed for one respiratory cycle elicit a significant decrease in the R—R interval. The present study was designed to determine if similar changes are produced by non-voluntary electrically evoked contractions and, if so, to establish the consistency and repeatability of the associated changes in the R—R interval. 2. The heart rate (R—R interval) response to voluntary or non-voluntary brief isometric contraction equivalent to 40% of the maximum voluntary contraction was studied in 10 healthy young male subjects during controlled ventilation at supine rest. 3. The absolute values of R—R intervals occurring in any one of 10 arbitrary phases of a respiratory cycle were measured and plotted by a computer. 4. Both voluntary and non-voluntary contractions elicited similar changes in heart rate and R—R interval, which were greater during expiration than during inspiration. 5. This confirms our previous finding that the magnitude of the R—R interval changes, with brief isometric contraction, is positively related to the degree of cardiac vagal tone. 6. Analysis of the variability between repeated tests initiated in either inspiration or expiration revealed that there was significantly less variability with the electrically induced contraction. 7. It was concluded that electrically induced contractions of 40% maximal voluntary contraction are a viable alternative to voluntary contractions and provide a more controllable means of measuring cardiac vagal withdrawal.

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Wei, Jiangpeng, Ying Zhang, Pengfei Yu, Xiuqin li, Xiangying Feng, Shisen li, Gang Ji, and Xiaohua Li. "Maximal voluntary ventilation and forced vital capacity of pulmonary function are independent prognostic factors in colorectal cancer patients." Medicine 100, no. 20 (May 21, 2021): e25793. http://dx.doi.org/10.1097/md.0000000000025793.

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Johnson, B. D., P. D. Scanlon, and K. C. Beck. "Regulation of ventilatory capacity during exercise in asthmatics." Journal of Applied Physiology 79, no. 3 (September 1, 1995): 892–901. http://dx.doi.org/10.1152/jappl.1995.79.3.892.

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In asthmatic and control subjects, we examined the changes in ventilatory capacity (VECap), end-expiratory lung volume (EELV), and degree of flow limitation during three types of exercise: 1) incremental, 2) constant load (50% of maximal exercise capacity; 36 min), and 3) interval (alternating between 60 and 40% of maximal exercise capacity; 6-min workloads for 36 min). The VECap and degree of flow limitation at rest and during the various stages of exercise were estimated by aligning the tidal breathing flow-volume (F-V) loops within the maximal expiratory F-V (MEFV) envelope using the measured EELV. In contrast to more usual estimates of VECap (i.e., maximal voluntary ventilation and forced expiratory volume in 1 s x 40), the calculated VECap depended on the existing bronchomotor tone, the lung volume at which the subjects breathed (i.e., EELV), and the tidal volume. During interval and constant-load exercise, asthmatic subjects experienced reduced ventilatory reserve, higher degrees of flow limitation, and had higher EELVs compared with nonasthmatic subjects. During interval exercise, the VECap of the asthmatic subjects increased and decreased with variations in minute ventilation, due in part to alterations in their MEFV curve as exercise intensity varied between 60 and 49% of maximal capacity. In conclusion, asthmatic subjects have a more variable VECap and reduced ventilatory reserve during exercise compared with nonasthmatic subjects. The variations in VECap are due in part to a more labile MEFV curve secondary to changes in bronchomotor tone. Asthmatics defend VECap and minimize flow limitation by increasing EELV.

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Nunes Júnior, Adauto de Oliveira, Marina Andrade Donzeli, Suraya Gomes Novais Shimano, Nuno Miguel Lopes de Oliveira, Gualberto Ruas, and Dernival Bertoncello. "EFFECTS OF HIGH-INTENSITY INSPIRATORY MUSCLE TRAINING IN RUGBY PLAYERS." Revista Brasileira de Medicina do Esporte 24, no. 3 (May 2018): 216–19. http://dx.doi.org/10.1590/1517-869220182403166216.

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ABSTRACT Introduction: Rugby is a sport characterized by high and low intensity motor action. Therefore, the respiratory muscles need adequate work to maintain sustained effective breathing. Objective: To analyze the effects of high-intensity inspiratory muscle training (IMT) in amateur rugby players from the city of Uberaba, Minas Gerais, Brazil. Methods: This is a clinical study in which 20 amateur players underwent a pulmonary function test, respiratory muscle strength and physical capacity assessment. The participants were divided into two groups: 10 volunteers in the IMT group (G1) and 10 in the control group (G2). All the assessments were carried out before and after 12 weeks of IMT. Results: No significant changes were observed in the pulmonary function test. However, maximal voluntary ventilation, maximal inspiratory pressure, maximal expiratory pressure and distance increased significantly after IMT. Conclusion: IMT had beneficial effects on amateur rugby players. Level of evidence I; Therapeutic studies - Investigation of treatment results.

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Chen, Qiu-Hong, Ri-Li Ge, Xiao-Zhen Wang, Hui-Xin Chen, Tian-Yi Wu, Toshio Kobayashi, and Kazuhiko Yoshimura. "Exercise performance of Tibetan and Han adolescents at altitudes of 3,417 and 4,300 m." Journal of Applied Physiology 83, no. 2 (August 1, 1997): 661–67. http://dx.doi.org/10.1152/jappl.1997.83.2.661.

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Chen, Qiu-Hong, Ri-Li Ge, Xiao-Zhen Wang, Hui-Xin Chen, Tian-Yi Wu, Toshio Kobayashi, and Kazuhiko Yoshimura. Exercise performance of Tibetan and Han adolescents at altitudes of 3,417 and 4,300 m. J. Appl. Physiol. 83(2): 661–667, 1997.—The difference was studied between O2 transport in lifelong Tibetan adolescents and in newcomer Han adolescents acclimatized to high altitude. We measured minute ventilation, maximal O2 uptake, maximal cardiac output, and arterial O2 saturation during maximal exercise, using the incremental exercise technique, at altitudes of 3,417 and 4,300 m. The groups were well matched for age, height, and nutritional status. The Tibetans had been living at the altitudes for a longer period than the Hans (14.5 ± 0.2 vs. 7.8 ± 0.8 yr at 3,417 m, P < 0.01; and 14.7 ± 0.3 vs. 5.3 ± 0.7 yr at 4,300 m, P < 0.01, respectively). At rest, Tibetans had significantly greater vital capacity and maximal voluntary ventilation than the Hans at both altitudes. At maximal exercise, Tibetans compared with Hans had higher maximal O2 uptake (42.2 ± 1.7 vs. 36.7 ± 1.2 ml ⋅ min−1 ⋅ kg−1at 3,417 m, P < 0.01; and 36.8 ± 1.9 vs. 30.0 ± 1.4 ml ⋅ min−1 ⋅ kg−1at 4,300 m, P < 0.01, respectively) and greater maximal cardiac output (12.8 ± 0.3 vs. 11.4 ± 0.2 l/min at 3,417 m, P < 0.01; 11.5 ± 0.5 vs. 10.0 ± 0.5 l/min at 4,300 m, P < 0.05, respectively). Although the differences in arterial O2saturation between Tibetans and Hans were not significant at rest and during mild exercise, the differences became greater with increases in exercise workload at both altitudes. We concluded that exposure to high altitude from birth to adolescence resulted in an efficient O2 transport and a greater aerobic exercise performance that may reflect a successful adaptation to life at high altitude.

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Kapreli, E., E. Vourazanis, E. Billis, JA Oldham, and N. Strimpakos. "Respiratory Dysfunction in Chronic Neck Pain Patients. A Pilot Study." Cephalalgia 29, no. 7 (July 2009): 701–10. http://dx.doi.org/10.1111/j.1468-2982.2008.01787.x.

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The aim of this pilot study was to add weight to a hypothesis according to which patients presenting with chronic neck pain could have a predisposition towards respiratory dysfunction. Twelve patients with chronic neck pain and 12 matched controls participated in this study. Spirometric values, maximal static pressures, forward head posture and functional tests were examined in all subjects. According to the results, chronic neck patients presented with a statistically significant decreased maximal voluntary ventilation ( P = 0.042) and respiratory muscle strength (Pimax and Pemax), ( P = 0.001 and P = 0.002, respectively). Furthermore, the current study demonstrated a strong association between an increased forward head posture and decreased respiratory muscle strength in neck pateits. The connection of neck pain and respiratory function could be an important consideration in relation to patient assessment, rehabilitation and consumption of pharmacological agents.

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Berry, M. J., R. G. McMurray, and V. L. Katz. "Pulmonary and ventilatory responses to pregnancy, immersion, and exercise." Journal of Applied Physiology 66, no. 2 (February 1, 1989): 857–62. http://dx.doi.org/10.1152/jappl.1989.66.2.857.

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To examine the effects of pregnancy, immersion, and exercise during immersion on pulmonary function and ventilation, 12 women were studied at 15, 25, and 35 wk of pregnancy and 8–10 wk postpartum. Pulmonary function and ventilation were measured under three experimental conditions: after 20 min of rest on land (LR), after 20 min of rest during immersion to the level of the xiphoid (IR), and after 20 min of exercise during immersion at 60% of predicted maximal capacity (IE). Forced vital capacity remained relatively constant, except for a decrease at 15 wk, for the duration of pregnancy. Expiratory reserve volume decreased with a change in the pregnancy status and with the duration of pregnancy. However, the forced vital capacity was maintained by an increase in the inspiratory capacity during pregnancy. Forced expiratory volume for 1 s, expressed as percent of forced vital capacity, did not differ significantly between conditions or as a result of pregnancy. Forced vital capacity was lower during the IR trial compared with LR and IE trials. The decreased forced vital capacity of the IR trials was mediated by a decrease in the expiratory reserve volume. Whereas the inspiratory capacity increased during IR and IE compared with LR, the increase was not large enough to offset the decrease in the expiratory reserve volume. Resting immersion resulted in a significant decrease in maximal voluntary ventilation as did pregnancy. Pregnancy resulted in significant increases in minute ventilation (VE), which were related to increases in the O2 consumption.(ABSTRACT TRUNCATED AT 250 WORDS)

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Belman, M. J., and G. A. Gaesser. "Ventilatory muscle training in the elderly." Journal of Applied Physiology 64, no. 3 (March 1, 1988): 899–905. http://dx.doi.org/10.1152/jappl.1988.64.3.899.

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To test the hypothesis that declining ventilatory function in the elderly impairs exercise capacity, we tested maximal exercise capacity and ventilatory function before and after a program of ventilatory muscle training in 25 elderly subjects (ages 65-75 yr). Ventilatory muscle training was performed by means of isocapnic hyperpnea for 30 min/day, 4 days/wk for 8 wk. Before and after the training, we measured maximal exercise capacity by means of an incremental exercise test (IET) and ventilatory muscle endurance by means of the maximum sustained ventilatory capacity (MSVC). Ratings of perceived exercise (RPE) for breathlessness and leg effort were evaluated each minute by means of a modified Borg scale during both the IET and a 12-min single-stage exercise test (SST) performed at approximately 70% of the maximal exercise capacity. The trained group showed a significant increase in the MSVC, from 71.9 ± 26.4 to 86.9 ± 20.9 l/min (P less than 0.01), whereas the control group showed no change (66.3 ± 22.5 to 65.1 ± 22.1 l/min). In addition, the maximal voluntary ventilation increased in the trained group, from 115 ± 41 to 135 ± 36 l/min (P less than 0.01). Neither the trained nor the control group showed an increase in maximum O2 uptake, maximum CO2 consumption, or maximum minute ventilation during the IET. Evaluation of the RPE during both the IET and SST showed that although there was a small decrease in RPE for breathing and leg discomfort, changes between the control and treated groups were similar.(ABSTRACT TRUNCATED AT 250 WORDS)

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Guenette, Jordan A., William R. Henderson, Paolo B. Dominelli, Jordan S. Querido, Penelope M. Brasher, Donald E. G. Griesdale, Robert Boushel, and A. William Sheel. "Blood flow index using near-infrared spectroscopy and indocyanine green as a minimally invasive tool to assess respiratory muscle blood flow in humans." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 300, no. 4 (April 2011): R984—R992. http://dx.doi.org/10.1152/ajpregu.00739.2010.

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Near-infrared spectroscopy (NIRS) in combination with indocyanine green (ICG) dye has recently been used to measure respiratory muscle blood flow (RMBF) in humans. This method is based on the Fick principle and is determined by measuring ICG in the respiratory muscles using transcutaneous NIRS in relation to the [ICG] in arterial blood as measured using photodensitometry. This method is invasive since it requires arterial cannulation, repeated blood withdrawals, and reinfusions. A less invasive alternative is to calculate a relative measure of blood flow known as the blood flow index (BFI), which is based solely on the NIRS ICG curve, thus negating the need for arterial cannulation. Accordingly, the purpose of this study was to determine whether BFI can be used to measure RMBF at rest and during voluntary isocapnic hyperpnea at 25, 40, 55, and 70% of maximal voluntary ventilation in seven healthy humans. BFI was calculated as the change in maximal [ICG] divided by the rise time of the NIRS-derived ICG curve. Intercostal and sternocleidomastoid muscle BFI were correlated with simultaneously measured work of breathing and electromyography (EMG) data from the same muscles. BFI showed strong relationships with the work of breathing and EMG for both respiratory muscles. The coefficients of determination ( R2) comparing BFI vs. the work of breathing for the intercostal and sternocleidomastoid muscles were 0.887 ( P < 0.001) and 0.863 ( P < 0.001), respectively, whereas the R2 for BFI vs. EMG for the intercostal and sternocleidomastoid muscles were 0.879 ( P < 0.001) and 0.930 ( P < 0.001), respectively. These data suggest that the BFI closely reflects RMBF in conscious humans across a wide range of ventilations and provides a less invasive and less technically demanding alternative to measuring RMBF.

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Durmic, Tijana, Biljana Lazovic, Marina Djelic, Jelena Suzic Lazic, Dejan Zikic, Vladimir Zugic, Milica Dekleva, and Sanja Mazic. "Sport-specific influences on respiratory patterns in elite athletes." Jornal Brasileiro de Pneumologia 41, no. 6 (December 2015): 516–22. http://dx.doi.org/10.1590/s1806-37562015000000050.

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ABSTRACT OBJECTIVE: To examine differences in lung function among sports that are of a similar nature and to determine which anthropometric/demographic characteristics correlate with lung volumes and flows. METHODS: This was a cross-sectional study involving elite male athletes (N = 150; mean age, 21 4 years) engaging in one of four different sports, classified according to the type and intensity of exercise involved. All athletes underwent full anthropometric assessment and pulmonary function testing (spirometry). RESULTS: Across all age groups and sport types, the elite athletes showed spirometric values that were significantly higher than the reference values. We found that the values for FVC, FEV1, vital capacity, and maximal voluntary ventilation were higher in water polo players than in players of the other sports evaluated (p < 0.001). In addition, PEF was significantly higher in basketball players than in handball players (p < 0.001). Most anthropometric/demographic parameters correlated significantly with the spirometric parameters evaluated. We found that BMI correlated positively with all of the spirometric parameters evaluated (p < 0.001), the strongest of those correlations being between BMI and maximal voluntary ventilation (r = 0.46; p < 0.001). Conversely, the percentage of body fat correlated negatively with all of the spirometric parameters evaluated, correlating most significantly with FEV1 (r = −0.386; p < 0.001). CONCLUSIONS: Our results suggest that the type of sport played has a significant impact on the physiological adaptation of the respiratory system. That knowledge is particularly important when athletes present with respiratory symptoms such as dyspnea, cough, and wheezing. Because sports medicine physicians use predicted (reference) values for spirometric parameters, the risk that the severity of restrictive disease or airway obstruction will be underestimated might be greater for athletes.

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Luo, Y. M., N. Hart, N. Mustfa, R. A. Lyall, M. I. Polkey, and J. Moxham. "Effect of diaphragm fatigue on neural respiratory drive." Journal of Applied Physiology 90, no. 5 (May 1, 2001): 1691–99. http://dx.doi.org/10.1152/jappl.2001.90.5.1691.

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To test the hypothesis that diaphragm fatigue leads to an increase in neural respiratory drive, we measured the esophageal diaphragm electromyogram (EMG) during CO2 rebreathing before and after diaphragm fatigue in six normal subjects. The electrode catheter was positioned on the basis of the amplitude and polarity of the diaphragm compound muscle action potential recorded simultaneously from four pairs of electrodes during bilateral anterior magnetic phrenic nerve stimulation (BAMPS) at functional residual capacity. Two minutes of maximum isocapnic voluntary ventilation (MIVV) were performed in six subjects to induce diaphragm fatigue. A maximal voluntary breathing against an inspiratory resistive loading (IRL) was also performed in four subjects. The reduction of transdiaphragmatic pressure elicited by BAMPS was 22% (range 13–27%) after 2 min of MIVV and was similar, 20% (range 13–26%), after IRL. There was a linear relationship between minute ventilation (V˙e) and the root mean square (RMS) of the EMG during CO2 rebreathing before and after fatigue. The mean slope of the linear regression of RMS on V˙e was similar before and after diaphragm fatigue: 2.80 ± 1.31 vs. 3.29 ± 1.40 for MIVV and 1.51 ± 0.31 vs 1.55 ± 0.31 for IRL, respectively. We conclude that the esophageal diaphragm EMG can be used to assess neural drive and that diaphragm fatigue of the intensity observed in this study does not affect respiratory drive.

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Cannon, Daniel T., Ana Claudia Coelho, Robert Cao, Andrew Cheng, Janos Porszasz, Richard Casaburi, and Harry B. Rossiter. "Skeletal muscle power and fatigue at the tolerable limit of ramp-incremental exercise in COPD." Journal of Applied Physiology 121, no. 6 (December 1, 2016): 1365–73. http://dx.doi.org/10.1152/japplphysiol.00660.2016.

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Muscle fatigue (a reduced power for a given activation) is common following exercise in chronic obstructive pulmonary disease (COPD). Whether muscle fatigue, and reduced maximal voluntary locomotor power, are sufficient to limit whole body exercise in COPD is unknown. We hypothesized in COPD: 1) exercise is terminated with a locomotor muscle power reserve; 2) reduction in maximal locomotor power is related to ventilatory limitation; and 3) muscle fatigue at intolerance is less than age-matched controls. We used a rapid switch from hyperbolic to isokinetic cycling to measure the decline in peak isokinetic power at the limit of incremental exercise (“performance fatigue”) in 13 COPD patients (FEV1 49 ± 17%pred) and 12 controls. By establishing the baseline relationship between muscle activity and isokinetic power, we apportioned performance fatigue into the reduction in muscle activation and muscle fatigue. Peak isokinetic power at intolerance was ~130% of peak incremental power in controls (274 ± 73 vs. 212 ± 84 W, P < 0.05), but ~260% in COPD patients (187 ± 141 vs. 72 ± 34 W, P < 0.05), greater than controls ( P < 0.05). Muscle fatigue as a fraction of baseline peak isokinetic power was not different in COPD patients vs. controls (0.11 ± 0.20 vs. 0.19 ± 0.11). Baseline to intolerance, the median frequency of maximal isokinetic muscle activity, was unchanged in COPD patients but reduced in controls (+4.3 ± 11.6 vs. −5.5 ± 7.6%, P < 0.05). Performance fatigue as a fraction of peak incremental power was greater in COPD vs. controls and related to resting (FEV1/FVC) and peak exercise (V̇E/maximal voluntary ventilation) pulmonary function ( r2 = 0.47 and 0.55, P < 0.05). COPD patients are more fatigable than controls, but this fatigue is insufficient to constrain locomotor power and define exercise intolerance.

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Amann, Markus, Lester T. Proctor, Joshua J. Sebranek, Marlowe W. Eldridge, David F. Pegelow, and Jerome A. Dempsey. "Somatosensory feedback from the limbs exerts inhibitory influences on central neural drive during whole body endurance exercise." Journal of Applied Physiology 105, no. 6 (December 2008): 1714–24. http://dx.doi.org/10.1152/japplphysiol.90456.2008.

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We investigated whether somatosensory feedback from contracting limb muscles exerts an inhibitory influence on the determination of central command during closed-loop cycling exercise in which the subject voluntarily determines his second-by-second central motor drive. Eight trained cyclists performed two 5-km time trials either without (5KCtrl) or with lumbar epidural anesthesia (5KEpi; 24 ml of 0.5% lidocaine, vertebral interspace L3–L4). Percent voluntary quadriceps muscle activation was determined at rest using a superimposed twitch technique. Epidural lidocaine reduced pretime trial maximal voluntary quadriceps strength (553 ± 45 N) by 22 ± 3%. Percent voluntary quadriceps activation was also reduced from 97 ± 1% to 81 ± 3% via epidural lidocaine, and this was unchanged following the 5KEpi, indicating the presence of a sustained level of neural impairment throughout the trial. Power output was reduced by 9 ± 2% throughout the race ( P < 0.05). We found three types of significant effects of epidural lidocaine that supported a substantial role for somatosensory feedback from the exercising limbs as a determinant of central command throughout high-intensity closed-loop cycling exercise: 1) significantly increased relative integrated EMG of the vastus lateralis; 2) similar pedal forces despite the reduced number of fast-twitch muscle fibers available for activation; 3) and increased ventilation out of proportion to a reduced carbon dioxide production and heart rate and increased blood pressure out of proportion to power output and oxygen consumption. These findings demonstrate the inhibitory influence of somatosensory feedback from contracting locomotor muscles on the conscious and/or subconscious determination of the magnitude of central motor drive during high intensity closed-loop endurance exercise.

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Dias, Olívia Meira, Bruno Guedes Baldi, Jeferson George Ferreira, Letícia Zumpano Cardenas, Francesca Pennati, Caterina Salito, Carlos Roberto Ribeiro Carvalho, Andrea Aliverti, and André Luis Pereira de Albuquerque. "Mechanisms of exercise limitation in patients with chronic hypersensitivity pneumonitis." ERJ Open Research 4, no. 3 (July 2018): 00043–2018. http://dx.doi.org/10.1183/23120541.00043-2018.

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Small airway and interstitial pulmonary involvements are prominent in chronic hypersensitivity pneumonitis (cHP). However, their roles on exercise limitation and the relationship with functional lung tests have not been studied in detail.Our aim was to evaluate exercise performance and its determinants in cHP. We evaluated maximal cardiopulmonary exercise testing performance in 28 cHP patients (forced vital capacity 57±17% pred) and 18 healthy controls during cycling.Patients had reduced exercise performance with lower peak oxygen production (16.6 (12.3–19.98) mL·kg−1·min−1versus 25.1 (16.9–32.0), p=0.003), diminished breathing reserve (% maximal voluntary ventilation) (12 (6.4–34.8)% versus 41 (32.7–50.8)%, p<0.001) and hyperventilation (minute ventilation/carbon dioxide production slope 37±5 versus 31±4, p<0.001). All patients presented oxygen desaturation and augmented Borg dyspnoea scores (8 (5–10) versus 4 (1–7), p=0.004). The prevalence of dynamic hyperinflation was found in only 18% of patients. When comparing cHP patients with normal and low peak oxygen production (<84% pred, lower limit of normal), the latter exhibited a higher minute ventilation/carbon dioxide production slope (39±5.0 versus 34±3.6, p=0.004), lower tidal volume (0.84 (0.78–0.90) L versus 1.15 (0.97–1.67) L, p=0.002), and poorer physical functioning score on the Short form-36 health survey. Receiver operating characteristic curve analysis showed that reduced lung volumes (forced vital capacity %, total lung capacity % and diffusing capacity of the lung for carbon dioxide %) were high predictors of poor exercise capacity.Reduced exercise capacity was prevalent in patients because of ventilatory limitation and not due to dynamic hyperinflation. Reduced lung volumes were reliable predictors of lower performance during exercise.

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Cory, Julia M., Michele R. Schaeffer, Sabrina S. Wilkie, Andrew H. Ramsook, Joseph H. Puyat, Brandon Arbour, Robbi Basran, et al. "Sex differences in the intensity and qualitative dimensions of exertional dyspnea in physically active young adults." Journal of Applied Physiology 119, no. 9 (November 1, 2015): 998–1006. http://dx.doi.org/10.1152/japplphysiol.00520.2015.

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Understanding sex differences in the qualitative dimensions of exertional dyspnea may provide insight into why women are more affected by this symptom than men. This study explored the evolution of the qualitative dimensions of dyspnea in 70 healthy, young, physically active adults (35 M and 35 F). Participants rated the intensity of their breathing discomfort (Borg 0-10 scale) and selected phrases that best described their breathing from a standardized list (work/effort, unsatisfied inspiration, and unsatisfied expiration) throughout each stage of a symptom-limited incremental-cycle exercise test. Following exercise, participants selected phrases that described their breathing at maximal exercise from a list of 15 standardized phrases. Intensity of breathing discomfort was significantly higher in women for a given ventilation, but differences disappeared when ventilation was expressed as a percentage of maximum voluntary ventilation. The dominant qualitative descriptor in both sexes throughout exercise was increased work/effort of breathing. At peak exercise, women were significantly more likely to select the following phrases: “my breathing feels shallow,” “I cannot get enough air in,” “I cannot take a deep breath in,” and “my breath does not go in all the way.” Women adopted a more rapid and shallow breathing pattern and had significantly higher end-inspiratory lung volumes relative to total lung capacity throughout exercise relative to men. These findings suggest that men and women do not differ in their perceived quality of dyspnea during submaximal exercise, but subjective differences appear at maximal exercise and may be related, at least in part, to underlying sex differences in breathing patterns and operating lung volumes during exercise.

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Campbell, EJM. "Multum in Parvo: Explorations with a Small Bag of Carbon Dioxide." Canadian Respiratory Journal 8, no. 4 (2001): 271–78. http://dx.doi.org/10.1155/2001/371284.

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A collection of 12 papers published between 1957 and 1972 are revisited. The papers had a common theme of the use of rebreathing carbon dioxide and explored a variety of topics in respiratory physiology. The first study established a method for the noninvasive and indirect estimation of arterial carbon dioxide pressure that was suitable for the routine clinical monitoring of respiratory failure and whose clinical utility remains to this day, but which also provided observations that were the stimulus for the studies that followed. The rate of rise in the partial pressure of carbon dioxide (PCO2) during rebreathing led to an analysis of body carbon dioxide storage capacity. Knowledge of carbon dioxide storage led to a method for quantifying lactate production in exercise without the need for blood sampling. The changes in ventilation that accompanied the increase inPCO2provided the basis for a rapid method for measuring aspects of breathing control (Read's method), which was later modified to measure the ventilatory response to hypoxia. The physiology of breath-holding was explored through observations of the fall in breath-holding time asPCO2climbed. Rebreathing also allowed increases in voluntary ventilation to be achieved without the development of alkalosis, leading to studies of maximal voluntary ventilation and respiratory muscle fatigue. Equilibration ofPCO2during rebreathing was used to measure mixed venousPCO2during exercise and develop an integrated approach to the physiology of exercise in health and disease; alveolar-arterial disequilibrium inPCO2during exercise was uncovered. Equilibration ofPCO2, as well asPO2, during rebreathing of carbon dioxide and nitrogen gas mixtures showed different time courses of venous gases at the onset of exercise. Starting with the rebreathing of carbon dioxide in oxygen mixtures in a small rubber bag, an astonishing range of topics in respiratory physiology was explored, with observations that remain valid, but in some respects unresolved, to the present day.

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Suh, Yujin, and Chaeyoung Lee. "Genome-wide association study for genetic variants related with maximal voluntary ventilation reveals two novel genomic signals associated with lung function." Medicine 96, no. 44 (November 2017): e8530. http://dx.doi.org/10.1097/md.0000000000008530.

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Journal articles on the topic 'Maximal voluntary ventilation'

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