Log in

Relevant bibliographies by topics / Breathing and heart rate[Hypoxia in man] / Journal articles

To see the other types of publications on this topic, follow the link: Breathing and heart rate[Hypoxia in man].

Journal articles on the topic 'Breathing and heart rate[Hypoxia in man]'

Author: Grafiati

Published: 4 June 2021

Last updated: 10 February 2022

Create a spot-on reference in APA, MLA, Chicago, Harvard, and other styles

Select a source type:

Consult the top 50 journal articles for your research on the topic 'Breathing and heart rate[Hypoxia in man].'

Next to every source in the list of references, there is an 'Add to bibliography' button. Press on it, and we will generate automatically the bibliographic reference to the chosen work in the citation style you need: APA, MLA, Harvard, Chicago, Vancouver, etc.

You can also download the full text of the academic publication as pdf and read online its abstract whenever available in the metadata.

Browse journal articles on a wide variety of disciplines and organise your bibliography correctly.

1

Kimura, Hiroshi, Yoshitake Nishibayashi, Fumiaki Hayashi, Akio Yoshida, and Yoshiyuki Honda. "Influence of Controlled Breathing with Diminished Tidal Volume on Hypoxic Heart Rate Response in Man." Respiration 54, no. 2 (1988): 103–9. http://dx.doi.org/10.1159/000195508.

Full text

APA, Harvard, Vancouver, ISO, and other styles

2

Calbet, J. A. L., R. Boushel, G. Rådegran, H. Søndergaard, P. D. Wagner, and B. Saltin. "Determinants of maximal oxygen uptake in severe acute hypoxia." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 284, no. 2 (2003): R291—R303. http://dx.doi.org/10.1152/ajpregu.00155.2002.

Full text

Abstract:

To unravel the mechanisms by which maximal oxygen uptake (V˙o 2 max) is reduced with severe acute hypoxia in humans, nine Danish lowlanders performed incremental cycle ergometer exercise to exhaustion, while breathing room air (normoxia) or 10.5% O2 in N2(hypoxia, ∼5,300 m above sea level). With hypoxia, exercise PaO2 dropped to 31–34 mmHg and arterial O2 content (CaO2 ) was reduced by 35% ( P < 0.001). Forty-one percent of the reduction in CaO2 was explained by the lower inspired O2 pressure (Pi O2 ) in hypoxia, whereas the rest was due to the impairment of the pulmonary gas exchange, as r

APA, Harvard, Vancouver, ISO, and other styles

3

Pal, A., M. A. Akey, R. Chatterjee, et al. "0556 Sex-Specific Relationship Between Anxiety and Autonomic Nervous System Dysfunction in Obstructive Sleep Apnea." Sleep 43, Supplement_1 (2020): A213. http://dx.doi.org/10.1093/sleep/zsaa056.553.

Full text

Abstract:

Abstract Introduction Cardiovascular co-morbidities in obstructive sleep apnea (OSA) are hard to treat, perhaps due to autonomic nervous system (ANS) dysfunction. In OSA, intermittent hypoxia and poor tissue oxygen perfusion damage endothelial and nervous tissue, potentially underlying the dysfunction. Moreover, OSA is strongly associated with anxiety, which is independently associated with ANS dysfunction. We assessed sex-specific relationships between anxiety and cardiovascular markers of ANS dysfunction in OSA. Methods We studied people diagnosed with OSA and healthy controls. We collected

APA, Harvard, Vancouver, ISO, and other styles

4

Tomi, Satoko T., Ryoji Ide, and Jacopo P. Mortola. "Heart and breathing rate variability in the avian perinatal period: The chicken embryo as a model." Avian Biology Research 12, no. 1 (2019): 13–22. http://dx.doi.org/10.1177/1758155919832137.

Full text

Abstract:

We used the chicken embryo at the internal pipping phase (just after the onset of pulmonary ventilation) as a model to quantify the changes in heart rate (fH), breathing frequency (fB) and their variabilities (heart rate variability and breathing rate variability) during air breathing (21% O2) and successive 20-min periods of 15%, 10% and 5% O2 and post-hypoxic recovery. For each condition, and for both fH and fB, variability was quantified by time-domain analysis with five standard criteria; these produced qualitatively similar results, which were combined into a single variability index. In

APA, Harvard, Vancouver, ISO, and other styles

5

DeBeck, Lindsay D., Stewart R. Petersen, Kelvin E. Jones, and Michael K. Stickland. "Heart rate variability and muscle sympathetic nerve activity response to acute stress: the effect of breathing." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 299, no. 1 (2010): R80—R91. http://dx.doi.org/10.1152/ajpregu.00246.2009.

Full text

Abstract:

Previous research has suggested a relationship between low-frequency power of heart rate variability (HRV; LF in normalized units, LFnu) and muscle sympathetic nerve activity (MSNA). However, investigations have not systematically controlled for breathing, which can modulate both HRV and MSNA. Accordingly, the aims of this experiment were to investigate the possibility of parallel responses in MSNA and HRV (LFnu) to selected acute stressors and the effect of controlled breathing. After data were obtained at rest, 12 healthy males (28 ± 5 yr) performed isometric handgrip exercise (30% maximal v

APA, Harvard, Vancouver, ISO, and other styles

6

Hermand, Eric, François J. Lhuissier, Aurélien Pichon, Nicolas Voituron, and Jean-Paul Richalet. "Exercising in Hypoxia and Other Stimuli: Heart Rate Variability and Ventilatory Oscillations." Life 11, no. 7 (2021): 625. http://dx.doi.org/10.3390/life11070625.

Full text

Abstract:

Periodic breathing is a respiratory phenomenon frequently observed in patients with heart failure and in normal subjects sleeping at high altitude. However, until recently, periodic breathing has not been studied in wakefulness and during exercise. This review relates the latest findings describing this ventilatory disorder when a healthy subject is submitted to simultaneous physiological (exercise) and environmental (hypoxia, hyperoxia, hypercapnia) or pharmacological (acetazolamide) stimuli. Preliminary studies have unveiled fundamental physiological mechanisms related to the genesis of peri

APA, Harvard, Vancouver, ISO, and other styles

7

Insalaco, Giuseppe, Salvatore Romano, Adriana Salvaggio, et al. "Blood pressure and heart rate during periodic breathing while asleep at high altitude." Journal of Applied Physiology 89, no. 3 (2000): 947–55. http://dx.doi.org/10.1152/jappl.2000.89.3.947.

Full text

Abstract:

The ventilatory and arterial blood pressure (ABP) responses to isocapnic hypoxia during wakefulness progressively increased in normal subjects staying 4 wk at 5,050 m (Insalaco G, Romano S, Salvaggio A, Braghiroli A, Lanfranchi P, Patruno V, Donner CF, and Bonsignore G; J Appl Physiol 80: 1724–1730, 1996). In the same subjects ( n = 5, age 28–34 yr) and expedition, nocturnal polysomnography with ABP and heart rate (HR) recordings were obtained during the 1st and 4th week to study the cardiovascular effects of phasic (i.e., periodic breathing-dependent) vs. tonic (i.e., acclimatization-dependen

APA, Harvard, Vancouver, ISO, and other styles

8

Parkes, M. J. "Evaluating the Importance of the Carotid Chemoreceptors in Controlling Breathing during Exercise in Man." BioMed Research International 2013 (2013): 1–18. http://dx.doi.org/10.1155/2013/893506.

Full text

Abstract:

Only the carotid chemoreceptors stimulate breathing during hypoxia in Man. They are also ideally located to warn if the brain’s oxygen supply falls, or if hypercapnia occurs. Since their discovery ~80 years ago stimulation, ablation, and recording experiments still leave 3 substantial difficulties in establishing how important the carotid chemoreceptors are in controlling breathing during exercise in Man: (i) they are in the wrong location to measure metabolic rate (but are ideally located to measure any mismatch), (ii) they receive no known signal during exercise linking them with metabolic r

APA, Harvard, Vancouver, ISO, and other styles

9

Siebenmann, Christoph, Camilla K. Ryrsø, Laura Oberholzer, et al. "Hypoxia-induced vagal withdrawal is independent of the hypoxic ventilatory response in men." Journal of Applied Physiology 126, no. 1 (2019): 124–31. http://dx.doi.org/10.1152/japplphysiol.00701.2018.

Full text

Abstract:

Hypoxia increases heart rate (HR) in humans by sympathetic activation and vagal withdrawal. However, in anaesthetized dogs hypoxia increases vagal activity and reduces HR if pulmonary ventilation does not increase and we evaluated whether that observation applies to awake humans. Ten healthy males were exposed to 15 min of normoxia and hypoxia (10.5% O2), while respiratory rate and tidal volume were volitionally controlled at values identified during spontaneous breathing in hypoxia. End-tidal CO2 tension was clamped at 40 mmHg by CO2 supplementation. β-Adrenergic blockade by intravenous propr

APA, Harvard, Vancouver, ISO, and other styles

10

Engelen, Marielle, Janos Porszasz, Marshall Riley, Karlman Wasserman, Kazuhira Maehara, and Thomas J. Barstow. "Effects of hypoxic hypoxia on O2 uptake and heart rate kinetics during heavy exercise." Journal of Applied Physiology 81, no. 6 (1996): 2500–2508. http://dx.doi.org/10.1152/jappl.1996.81.6.2500.

Full text

Abstract:

Engelen, Marielle, Janos Porszasz, Marshall Riley, Karlman Wasserman, Kazuhira Maehara, and Thomas J. Barstow. Effects of hypoxic hypoxia on O2 uptake and heart rate kinetics during heavy exercise. J. Appl. Physiol. 81(6): 2500–2508, 1996.—It is unclear whether hypoxia alters the kinetics of O2 uptake (V˙o 2) during heavy exercise [above the lactic acidosis threshold (LAT)] and how these alterations might be linked to the rise in blood lactate. Eight healthy volunteers performed transitions from unloaded cycling to the same absolute heavy work rate for 8 min while breathing one of three inspir

APA, Harvard, Vancouver, ISO, and other styles

11

Finley, John P., and C. Kelly. "Heart rate and respiratory patterns in mild hypoxia in unanaesthetized newborn mammals." Canadian Journal of Physiology and Pharmacology 64, no. 2 (1986): 122–24. http://dx.doi.org/10.1139/y86-018.

Full text

Abstract:

The heart rate and respiratory patterns in hypoxia are not well documented in unanaesthetized intact newborn animals. We studied heart rate and respiratory patterns during quiet sleep in 17% inspired O2 in 31 unanaesthetized newborns of five species: lamb, piglet, puppy, kitten, and rabbit. There was no significant change in mean heart rate and respiratory rate with hypoxia for any species. Brief apneas greater than 5 s were frequent (5–8/h), both in 21 and 17% O2 only in lambs and puppies. No sustained periodic breathing was induced by hypoxia. Thus, mild hypoxia has little steady-state effec

APA, Harvard, Vancouver, ISO, and other styles

12

Cooper, D. M., D. H. Wasserman, M. Vranic, and K. Wasserman. "Glucose turnover in response to exercise during high- and low-FIO2 breathing in man." American Journal of Physiology-Endocrinology and Metabolism 251, no. 2 (1986): E209—E214. http://dx.doi.org/10.1152/ajpendo.1986.251.2.e209.

Full text

Abstract:

The purpose of this study was to assess whether breathing high or low concentrations of O2 could affect glucose turnover during exercise in man. Ten healthy subjects performed two constant work-rate exercise tests, one when the fraction of inspired O2 (FIO2) was 0.15 and the other at the same work rate but when the FIO2 was 0.80. The work rate for each subject was chosen so that blood lactate would be elevated during hypoxia, but would be lower during hyperoxia. Glucose appearance (Ra) and disappearance (Rd) were measured using the primed, constant infusion of [3-3H]glucose. Although the work

APA, Harvard, Vancouver, ISO, and other styles

13

Kaijser, L., J. Pernow, B. Berglund, J. Grubbstrom, and J. M. Lundberg. "Neuropeptide Y release from human heart is enhanced during prolonged exercise in hypoxia." Journal of Applied Physiology 76, no. 3 (1994): 1346–49. http://dx.doi.org/10.1152/jappl.1994.76.3.1346.

Full text

Abstract:

To evaluate the effect of hypoxemia on cardiac release of neuropeptide Y-like immunoreactivity (NPY-LI) and norepinephrine (NE), arterial and coronary sinus blood was sampled and coronary sinus blood flow was measured by thermodilution in nine healthy volunteers at rest and during supine cycle ergometer exercise while they breathed air and 12% O2, which reduced arterial O2 saturation to approximately 68%. Five subjects started to exercise for 30 min breathing air and continued for 30 min breathing 12% O2; four subjects breathed 12% O2 and air in the reverse order. The load was adjusted to give

APA, Harvard, Vancouver, ISO, and other styles

14

Chau, Andrew, and Brian J. Koos. "Metabolic and cardiorespiratory responses to hypoxia in fetal sheep: adenosine receptor blockade." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 276, no. 6 (1999): R1805—R1811. http://dx.doi.org/10.1152/ajpregu.1999.276.6.r1805.

Full text

Abstract:

8-Phenyltheophylline (PT), a potent and specific inhibitor of adenosine receptors, was infused intra-arterially into unanesthetized fetal sheep to determine the role of adenosine in hypoxic inhibition of fetal breathing. PT in normoxic fetuses increased heart rate and the incidence of low-voltage electrocortical activity, rapid eye movements (REM), and breathing. Mean breath amplitude increased by 44%. Hypoxia (preductal arterial[Formula: see text] = 14 Torr) induced a metabolic acidemia, a transient bradycardia, and hypertension while virtually eliminating REM and breathing. PT administration

APA, Harvard, Vancouver, ISO, and other styles

15

Galletly, D. C., P. D. Tobin, B. J. Robinson, and T. Corfiatis. "Effect of Inhalation of 30% Nitrous Oxide on Spectral Components of Heart Rate Variability in Conscious man." Clinical Science 85, no. 4 (1993): 389–92. http://dx.doi.org/10.1042/cs0850389.

Full text

Abstract:

1. Periodicities in cardiac interbeat interval may be resolved into discrete frequency components by applying Fourier analysis to heart rate time series. Low-frequency components (<0.15 Hz) are believed to be under parasympathetic and sympathetic control, whereas a higher frequency component in phase with respiration is believed to be entirely parasympathetic. The ratio of the power in the low-/high-frequency spectrum gives an estimate of sympathetic/para-sympathetic balance. 2. This study examined, using heart rate variability spectral analysis, the cardiac autonomic effects of breathing 3

APA, Harvard, Vancouver, ISO, and other styles

16

Rocha, P. L., and L. G. S. Branco. "Seasonal changes in the cardiovascular, respiratory and metabolic responses to temperature and hypoxia in the bullfrog rana catesbeiana." Journal of Experimental Biology 201, no. 5 (1998): 761–68. http://dx.doi.org/10.1242/jeb.201.5.761.

Full text

Abstract:

We assessed seasonal variations in the effects of temperature on hypoxia-induced alterations in the bullfrog Rana catesbeiana by measuring the heart rate, arterial blood pressure, breathing frequency, metabolic rate, blood gas levels, acid-base status and plasma glucose concentration. Regardless of the season, decreased body temperature was accompanied by a reduction in heart and breathing frequencies. Lower temperatures caused a significant decrease in arterial blood pressure during all four seasons. Hypoxia-induced changes in breathing frequency were proportional to body temperature and were

APA, Harvard, Vancouver, ISO, and other styles

17

LUNDBY, Carsten, Peter MØLLER, Inge-Lis KANSTRUP, and Niels Vidiendal OLSEN. "Heart rate response to hypoxic exercise: role of dopamine D2-receptors and effect of oxygen supplementation." Clinical Science 101, no. 4 (2001): 377–83. http://dx.doi.org/10.1042/cs1010377.

Full text

Abstract:

This study examined the effects of dopamine D2-receptor blockade on the early decrease in maximal heart rate at high altitude (4559m). We also attempted to clarify the time-dependent component of this reduction and the extent to which it is reversed by oxygen breathing. Twelve subjects performed two consecutive maximal exercise tests, without and with oxygen supplementation respectively, at sea level and after 1, 3 and 5 days at altitude. On each study day, domperidone (30mg; n = 6) or no medication (n = 6) was given 1h before the first exercise session. Compared with sea level, hypoxia progre

APA, Harvard, Vancouver, ISO, and other styles

18

Koos, B. J., and K. Matsuda. "Fetal breathing, sleep state, and cardiovascular responses to adenosine in sheep." Journal of Applied Physiology 68, no. 2 (1990): 489–95. http://dx.doi.org/10.1152/jappl.1990.68.2.489.

Full text

Abstract:

The possibility that adenosine mediates hypoxic inhibition of fetal breathing and eye movements was tested in nine chronically catheterized fetal sheep (0.8 term). Intracarotid infusion of adenosine (0.25 +/- 0.03 mg.min-1.kg-1) for 1 h to the fetus increased heart rate and hemoglobin concentration but did not significantly affect mean arterial pressure or blood gases. As with hypoxia, adenosine decreased the incidence of rapid eye movements by 55% and the incidence of breathing by 77% without significantly affecting the incidence of low-voltage electrocortical activity. However, with longer (

APA, Harvard, Vancouver, ISO, and other styles

19

Van Eyck, Annelies, Kim Van Hoorenbeeck, Benedicte Y. De Winter, Luc Van Gaal, Wilfried De Backer, and Stijn L. Verhulst. "Sleep disordered breathing and autonomic function in overweight and obese children and adolescents." ERJ Open Research 2, no. 4 (2016): 00038–2016. http://dx.doi.org/10.1183/23120541.00038-2016.

Full text

Abstract:

Obstructive sleep apnoea (OSA), common in children with obesity, is associated with cardiovascular morbidity. Autonomic dysfunction has been suggested to be a key player in the development of these complications. We investigated the relationship between obesity, OSA and sympathetic activity in children.191 children with obesity were included and distributed into two groups: 131 controls and 60 with OSA. Beat-to-beat RR interval data were extracted from polysomnography for heart rate variability analysis. Urinary free cortisol levels were determined.Urinary free cortisol did not differ between

APA, Harvard, Vancouver, ISO, and other styles

20

Dominelli, Paolo B., Sarah E. Baker, Chad C. Wiggins, et al. "Dissociating the effects of oxygen pressure and content on the control of breathing and acute hypoxic response." Journal of Applied Physiology 127, no. 6 (2019): 1622–31. http://dx.doi.org/10.1152/japplphysiol.00569.2019.

Full text

Abstract:

Arterial oxygen tension and oxyhemoglobin saturation ([Formula: see text]) decrease in parallel during hypoxia. Distinguishing between changes in oxygen tension and oxygen content as the relevant physiological stimulus for cardiorespiratory alterations remains challenging. To overcome this, we recruited nine individuals with hemoglobinopathy manifesting as high-affinity hemoglobin [HAH; partial pressure at 50% [Formula: see text] (P50) = 16 ± 0.4 mmHg] causing greater [Formula: see text] at a given oxygen partial pressure compared with control subjects ( n = 12, P50 = 26 ± 0.4 mmHg). We assess

APA, Harvard, Vancouver, ISO, and other styles

21

O'Hagan, K. P., L. B. Bell, and P. S. Clifford. "Effects of pulmonary denervation on renal sympathetic and heart rate responses to hypoxia." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 269, no. 4 (1995): R923—R929. http://dx.doi.org/10.1152/ajpregu.1995.269.4.r923.

Full text

Abstract:

We hypothesized that the renal sympathetic nerve activity (RSNA) response to hypoxia is attenuated because of stimulation of pulmonary receptors by the increase in ventilation. RSNA was measured during 20 min of severe hypoxia (8% O2) in conscious New Zealand White rabbits with intact lung innervation and in rabbits with surgical denervation of the lungs (LDX). LDX decreased resting breathing frequency but had no effect on resting mean arterial pressure (MAP), heart rate (HR), or RSNA. In intact rabbits, 4 min of hypoxia resulted in elevated RSNA (from 14 +/- 2 to 29 +/- 3% of smoke-elicited m

APA, Harvard, Vancouver, ISO, and other styles

22

OHYABU, YOSHIO, MIDORI SATO, and YOSHIYUKI HONDA. "ENHANCED VENTILATORY AND HEART RATE RESPONSIVENESS TO HYPOXIA DURING MODERATE EXERCISE IN MAN." Japanese Journal of Physical Fitness and Sports Medicine 37, no. 1 (1988): 93–99. http://dx.doi.org/10.7600/jspfsm1949.37.93.

Full text

APA, Harvard, Vancouver, ISO, and other styles

23

Reeves, J. T., B. M. Groves, J. R. Sutton, et al. "Operation Everest II: preservation of cardiac function at extreme altitude." Journal of Applied Physiology 63, no. 2 (1987): 531–39. http://dx.doi.org/10.1152/jappl.1987.63.2.531.

Full text

Abstract:

Hypoxia at high altitude could depress cardiac function and decrease exercise capacity. If so, impaired cardiac function should occur with the extreme, chronic hypoxemia of the 40-day simulated climb of Mt. Everest (8,840 m, barometric pressure of 240 Torr, inspiratory O2 pressure of 43 Torr). In the five of eight subjects having resting and exercise measurements at the barometric pressures of 760 Torr (sea level), 347 Torr (6,100 m), 282 Torr (7,620 m), and 240 Torr, heart rate for a given O2 uptake was higher with more severe hypoxia. Slight (6 beats/min) slowing of the heart rate occurred o

APA, Harvard, Vancouver, ISO, and other styles

24

Mendoza, James P., Rachael J. Passafaro, Santhosh M. Baby, et al. "Role of nitric oxide-containing factors in the ventilatory and cardiovascular responses elicited by hypoxic challenge in isoflurane-anesthetized rats." Journal of Applied Physiology 116, no. 11 (2014): 1371–81. http://dx.doi.org/10.1152/japplphysiol.00842.2013.

Full text

Abstract:

Exposure to hypoxia elicits changes in mean arterial blood pressure (MAP), heart rate, and frequency of breathing (fr). The objective of this study was to determine the role of nitric oxide (NO) in the cardiovascular and ventilatory responses elicited by brief exposures to hypoxia in isoflurane-anesthetized rats. The rats were instrumented to record MAP, heart rate, and fr and then exposed to 90 s episodes of hypoxia (10% O2, 90% N2) before and after injection of vehicle, the NO synthase inhibitor NG-nitro-l-arginine methyl ester (l-NAME), or the inactive enantiomer d-NAME (both at 50 μmol/kg

APA, Harvard, Vancouver, ISO, and other styles

25

MacCormack, T. J., R. S. McKinley, R. Roubach, V. M. F. Almeida-Val, A. L. Val, and W. R. Driedzic. "Changes in ventilation, metabolism, and behaviour, but not bradycardia, contribute to hypoxia survival in two species of Amazonian armoured catfish." Canadian Journal of Zoology 81, no. 2 (2003): 272–80. http://dx.doi.org/10.1139/z03-003.

Full text

Abstract:

Amazonian armoured catfishes exhibit substantial cardiac hypoxia tolerance, but little is known concerning organismal cardiorespiratory, metabolic, and behavioural responses to low oxygen levels. This study assessed the general mechanisms used by two species of armoured catfish, Glyptoperichthyes gibbceps and Liposarcus pardalis, to survive the frequent periods of hypoxia encountered in the Amazon River. The gill ventilation rate (fv) and heart rate (fh) were studied under controlled hypoxia in aquaria and under natural hypoxia in a simulated pond. Glyptoperichthyes gibbceps were fitted with r

APA, Harvard, Vancouver, ISO, and other styles

26

Liu, Chun, Quentin P. P. Croft, Swati Kalidhar, et al. "Dexamethasone mimics aspects of physiological acclimatization to 8 hours of hypoxia but suppresses plasma erythropoietin." Journal of Applied Physiology 114, no. 7 (2013): 948–56. http://dx.doi.org/10.1152/japplphysiol.01414.2012.

Full text

Abstract:

Dexamethasone ameliorates the severity of acute mountain sickness (AMS) but it is unknown whether it obtunds normal physiological responses to hypoxia. We studied whether dexamethasone enhanced or inhibited the ventilatory, cardiovascular, and pulmonary vascular responses to sustained (8 h) hypoxia. Eight healthy volunteers were studied, each on four separate occasions, permitting four different protocols. These were: dexamethasone (20 mg orally) beginning 2 h before a control period of 8 h of air breathing; dexamethasone with 8 h of isocapnic hypoxia (end-tidal Po2 = 50 Torr); placebo with 8

APA, Harvard, Vancouver, ISO, and other styles

27

Xue, Yong, Jun Yang, Yutao Feng, et al. "Effects of Mindful Breathing on Rapid Hypoxia Preacclimatization Training." Journal of Medical Imaging and Health Informatics 10, no. 3 (2020): 718–23. http://dx.doi.org/10.1166/jmihi.2020.2923.

Full text

Abstract:

Rapid exposure at high altitude is likely to cause Acute Mountain Sickness (AMS) of different levels. This paper designs a "quick acclimatization" method to make the volunteers adapt to 3,600 meters (m) after 2-day training and 3,900 m after 3-day training. Especially, we investigate the effects of mindful breathing on rapid hypoxia preacclimatization training. 8 young male volunteers were randomly divided into one treatment group and one control group. Peripheral Saturation of Oxygen (SpO2), Heart Rate (HR) and Respiratory Rate (RR) were recorded from the beginning to the end. We find that: (

APA, Harvard, Vancouver, ISO, and other styles

28

Robinson, K. A., and E. M. Haymes. "Metabolic effects of exposure to hypoxia plus cold at rest and during exercise in humans." Journal of Applied Physiology 68, no. 2 (1990): 720–25. http://dx.doi.org/10.1152/jappl.1990.68.2.720.

Full text

Abstract:

To determine effects on metabolic responses, subjects were exposed to four environmental conditions for 90 min at rest followed by 30 min of exercise: breathing room air with an ambient temperature of 25 degrees C (NN); breathing room air with an ambient temperature of 8 degrees C (NC); hypoxia (induced by breathing 12% O2 in N2) with a neutral temperature (HN); and hypoxia in the cold (HC). Hypoxia increased heart rate (HR), systolic blood pressure (SBP), pulmonary ventilation (VE), respiratory exchange ratio (R), blood lactate, and perceived exertion during exercise while depressing rectal t

APA, Harvard, Vancouver, ISO, and other styles

29

Del Rio, Rodrigo, Noah J. Marcus, and Harold D. Schultz. "Inhibition of hydrogen sulfide restores normal breathing stability and improves autonomic control during experimental heart failure." Journal of Applied Physiology 114, no. 9 (2013): 1141–50. http://dx.doi.org/10.1152/japplphysiol.01503.2012.

Full text

Abstract:

Cardiovascular autonomic imbalance and breathing instability are major contributors to the progression of heart failure (CHF). Potentiation of the carotid body (CB) chemoreflex has been shown to contribute to these effects. Hydrogen sulfide (H2S) recently has been proposed to mediate CB hypoxic chemoreception. We hypothesized that H2S synthesis inhibition should decrease CB chemoreflex activation and improve breathing stability and autonomic function in CHF rats. Using the irreversible inhibitor of cystathione γ-lyase dl-propargylglycine (PAG), we tested the effects of H2S inhibition on restin

APA, Harvard, Vancouver, ISO, and other styles

30

TANAKA, M., S. TAKAISHI, T. OHDAIRA, et al. "Dependence of Biphasic Heart Rate Response to Sustained Hypoxia on Magnitude of Ventilation in Man." Japanese Journal of Physiology 42, no. 6 (1992): 865–75. http://dx.doi.org/10.2170/jjphysiol.42.865.

Full text

APA, Harvard, Vancouver, ISO, and other styles

31

Halliwill, John R., and Christopher T. Minson. "Cardiovagal regulation during combined hypoxic and orthostatic stress: fainters vs. nonfainters." Journal of Applied Physiology 98, no. 3 (2005): 1050–56. http://dx.doi.org/10.1152/japplphysiol.00871.2004.

Full text

Abstract:

We tested the hypothesis that individual differences in the effect of acute hypoxia on the cardiovagal arterial baroreflex would determine individual susceptibility to hypoxic syncope. In 16 healthy, nonsmoking, normotensive subjects (8 women, 8 men, age 20–33 yr), we assessed orthostatic tolerance with a 20-min 60° head-upright tilt during both normoxia and hypoxia (breathing 12% O2). On a separate occasion, we assessed baroreflex control of heart rate (cardiovagal baroreflex gain) using the modified Oxford technique during both normoxia and hypoxia. When subjects were tilted under hypoxic co

APA, Harvard, Vancouver, ISO, and other styles

32

Leuenberger, Urs A., J. Cullen Hardy, Michael D. Herr, Kristen S. Gray, and Lawrence I. Sinoway. "Hypoxia augments apnea-induced peripheral vasoconstriction in humans." Journal of Applied Physiology 90, no. 4 (2001): 1516–22. http://dx.doi.org/10.1152/jappl.2001.90.4.1516.

Full text

Abstract:

Obstructive apnea and voluntary breath holding are associated with transient increases in muscle sympathetic nerve activity (MSNA) and arterial pressure. The contribution of changes in blood flow relative to the contribution of changes in vascular resistance to the apnea-induced transient rise in arterial pressure is unclear. We measured heart rate, mean arterial blood pressure (MAP), MSNA (peroneal microneurography), and femoral artery blood velocity ( V FA, Doppler) in humans during voluntary end-expiratory apnea while they were exposed to room air, hypoxia (10.5% inspiratory fraction of O2)

APA, Harvard, Vancouver, ISO, and other styles

33

Piazza, Tiziana, Anne Marie Lauzon, and Jacopo P. Mortola. "Time course of adaptation to hypoxia in newborn rats." Canadian Journal of Physiology and Pharmacology 66, no. 1 (1988): 152–58. http://dx.doi.org/10.1139/y88-027.

Full text

Abstract:

In newborn rats after a few minutes of hypoxia, ventilation is similar to the normoxic value. Nevertheless, after a few days in hypoxia, newborn rats have a sustained hyperventilation. In this study we examined the time course of the newborn rat's adaptation to hypoxia. Measurements of body size, hematocrit, lung and heart mass, and breathing pattern have been performed on newborn rats exposed to hypoxia (10% O2) for different time intervals from 4 to 60 h (hypoxic, H), and on same-age rats growing in air (controls, C). Ventilation measured by flow plethysmography was increased in H rats above

APA, Harvard, Vancouver, ISO, and other styles

34

Zerbini, Livio, Alfredo Brighenti, Barbara Pellegrini, Lorenzo Bortolan, Tommaso Antonetti, and Federico Schena. "Effects of acute hypoxia on the oxygen uptake kinetics of older adults during cycling exercise." Applied Physiology, Nutrition, and Metabolism 37, no. 4 (2012): 744–52. http://dx.doi.org/10.1139/h2012-048.

Full text

Abstract:

Pulmonary oxygen uptake, heart rate (HR), and deoxyhemoglobin (HHb) kinetics were studied in a group of older adults exercising in hypoxic conditions. Fourteen healthy older adults (aged 66 ± 6 years) performed 4 exercise sessions that consisted of (i) an incremental test to exhaustion on a cycloergometer while breathing normoxic room air (fractional inspired oxygen (FiO2) = 20.9% O2); (ii) an incremental test to exhaustion on a cycloergometer while breathing hypoxic room air (FiO2 = 15% O2); (iii) 3 repeated square wave cycling exercises at moderate intensity while breathing normoxic room air

APA, Harvard, Vancouver, ISO, and other styles

35

Giesbrecht, G. G., A. Puddy, M. Ahmed, M. Younes, and N. R. Anthonisen. "Exercise endurance and arterial desaturation in normobaric hypoxia with increased chemosensitivity." Journal of Applied Physiology 70, no. 4 (1991): 1770–74. http://dx.doi.org/10.1152/jappl.1991.70.4.1770.

Full text

Abstract:

We studied whether exercise endurance under normobaric hypoxia can be enhanced by increasing hypoxic ventilatory sensitivity with almitrine bismesylate (ALM). On both ALM and placebo (PL) days, resting subjects breathed a hypoxic gas mixture (an inspired O2 fraction of 10.4-13.2%), which lowered resting arterial O2 saturation (SaO2) to 80%. After 15 min of rest there was a 3-min warm-up period of exercise at 50 W (light) on a cycle ergometer, followed by a step increase in load to 60% of the previously determined maximum power output with room-air breathing (moderate), which was maintained unt

APA, Harvard, Vancouver, ISO, and other styles

36

Furilla, R. A., and D. R. Jones. "The contribution of nasal receptors to the cardiac response to diving in restrained and unrestrained redhead ducks (Aythya americana)." Journal of Experimental Biology 121, no. 1 (1986): 227–38. http://dx.doi.org/10.1242/jeb.121.1.227.

Full text

Abstract:

In restrained redhead ducks, forced submergence caused heart rate to fall from 100 +/− 3 beats min-1 (mean +/− S.E.M., N = 12) to a stable underwater rate of 35 +/− 4 beats min-1 (N = 12) within 5 s after submergence. Bradycardia was unaffected by breathing oxygen before a dive, but was virtually eliminated by local anaesthesia of the narial region. In contrast, in a dabbling duck (Anas platyrhynchos) bradycardia in short dives was eliminated by breathing oxygen before a dive. In unrestrained diving, on a man-made pond, heart rate in redheads diving voluntarily (y) was related to pre-dive hear

APA, Harvard, Vancouver, ISO, and other styles

37

Smatresk, N. J., M. L. Burleson, and S. Q. Azizi. "Chemoreflexive responses to hypoxia and NaCN in longnose gar: evidence for two chemoreceptor loci." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 251, no. 1 (1986): R116—R125. http://dx.doi.org/10.1152/ajpregu.1986.251.1.r116.

Full text

Abstract:

Interactions between internal and external O2 stimulus levels were assessed by measuring the ventilatory and cardiovascular responses to varying water (PWO2) and air bladder (PabO2) O2 levels and intravascular NaCN in anesthetized spontaneously ventilating Lepisosteus osseus. As PWO2 fell, air-breathing frequency (fab) increased. Buccal pressure amplitude (Pb) also increased as PWO2 fell from hyperoxia to normoxia, but hypoxic water depressed Pb. The PO2 in the ventral aorta (VA) fell as PabO2 fell, which stimulated fab and Pb when the gar was in normoxic or hyperoxic water. Thus gill ventilat

APA, Harvard, Vancouver, ISO, and other styles

38

HEDRICK, M. S., M. L. BURLESON, D. R. JONES, and W. K. MILSOM. "An Examination of Central Chemosensitivity in an Air-Breathing Fish (Amia Calva)." Journal of Experimental Biology 155, no. 1 (1991): 165–74. http://dx.doi.org/10.1242/jeb.155.1.165.

Full text

Abstract:

The role of central chemosensitivity in the control of ventilation in fishes was investigated directly by perfusing a mock extradural fluid (EDF) through the cranial space in the medullary region of conscious air-breathing fish, Amia calva. Perfusions with Sudan Black dye showed that the mock EDF communicated with the cerebrospinal fluid (CSF) and entered the cerebral ventricles. Altering the PO2, PCO2 and/or pH of the mock EDF had no effect on gill- or air-breathing rates, heart rate or blood pressure during exposure to normoxic water. Aquatic hypoxia, however, stimulated gill ventilation and

APA, Harvard, Vancouver, ISO, and other styles

39

Curtis, Andrew N., Michael L. Walsh, and Matthew D. White. "Influence of passive hyperthermia on human ventilation during rest and isocapnic hypoxia." Applied Physiology, Nutrition, and Metabolism 32, no. 4 (2007): 721–32. http://dx.doi.org/10.1139/h07-035.

Full text

Abstract:

The purpose of this study was to examine the potential interaction of core temperature and isocapnic hypoxia on human ventilation and heart rate (HR). In 2 resting head-out water-immersion trials, 8 males first breathed air and then 12% O2 in N2 while the end-tidal partial pressure of carbon dioxide was kept 0.98 (0.66) mmHg (mean (SD)) above normothermic resting levels. The first immersion trial was with a normothermic esophageal temperature (Tes) of ~36.7 °C, and for the second trial, 1 h later, water temperature was increased to give a hyperthermic Tes of ~38.2 °C. Isocapnic hypoxia increas

APA, Harvard, Vancouver, ISO, and other styles

40

Kinsman, Tahnee A., Allan G. Hahn, Christopher J. Gore, Bradley R. Wilsmore, David T. Martin, and Chin-Moi Chow. "Respiratory events and periodic breathing in cyclists sleeping at 2,650-m simulated altitude." Journal of Applied Physiology 92, no. 5 (2002): 2114–18. http://dx.doi.org/10.1152/japplphysiol.00737.2001.

Full text

Abstract:

We examined the initial effect of sleeping at a simulated moderate altitude of 2,650 m on the frequency of apneas and hypopneas, as well as on the heart rate and blood oxygen saturation from pulse oximetry (SpO2 ) during rapid eye movement (REM) and non-rapid eye movement (NREM) sleep of 17 trained cyclists. Pulse oximetry revealed that sleeping at simulated altitude significantly increased heart rate (3 ± 1 beats/min; means ± SE) and decreased SpO2 (−6 ± 1%) compared with baseline data collected near sea level. In response to simulated altitude, 15 of the 17 subjects increased the combined fr

APA, Harvard, Vancouver, ISO, and other styles

41

van den Aardweg, J. G., and J. M. Karemaker. "Repetitive apneas induce periodic hypertension in normal subjects through hypoxia." Journal of Applied Physiology 72, no. 3 (1992): 821–27. http://dx.doi.org/10.1152/jappl.1992.72.3.821.

Full text

Abstract:

Periodic increases in blood pressure (BP) can occur in the sleep apnea syndrome (SAS) during recurrent apneas. To investigate the mechanisms causing this periodic hypertension, we simulated SAS by imposing a matching breathing pattern on seven healthy awake male volunteers. Continuous finger arterial BP, electrocardiogram, arterial O2 saturation (SaO2), end-tidal CO2, and tidal volume were measured. The role of hypoxia was studied by comparing apneas during depletion of O2 in the spirometer with those during 100% O2 breathing. In all subjects, BP periodically reached values greater than 150/95

APA, Harvard, Vancouver, ISO, and other styles

42

Huang, J., C. Suguihara, D. Hehre, J. Lin, and E. Bancalari. "Effects of GABA receptor blockage on the respiratory response to hypoxia in sedated newborn piglets." Journal of Applied Physiology 77, no. 2 (1994): 1006–10. http://dx.doi.org/10.1152/jappl.1994.77.2.1006.

Full text

Abstract:

Brain gamma-aminobutyric acid (GABA) levels increase during hypoxia, which may modulate the ventilatory response to hypoxia. To test the possibility that the depressed neonatal ventilatory response to hypoxia may be related to increased central nervous system GABA activity, 26 sedated spontaneously breathing newborn piglets (age 5 +/- 1 day, wt 1.7 +/- 0.4 kg) were studied. Minute ventilation (VE), oxygen consumption, heart rate, arterial blood pressure, and arterial blood gases were measured in room air and after 1, 5, and 10 min of hypoxia (inspired O2 fraction 0.10) before drug intervention

APA, Harvard, Vancouver, ISO, and other styles

43

Barrett, Karlene T., Shabih U. Hasan, Morris H. Scantlebury, and Richard J. A. Wilson. "Impaired neonatal cardiorespiratory responses to hypoxia in mice lacking PAC1 or VPAC2 receptors." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 316, no. 5 (2019): R594—R606. http://dx.doi.org/10.1152/ajpregu.00250.2018.

Full text

Abstract:

The stress peptide pituitary adenylate cyclase activating polypeptide (PACAP) and its specific receptor PACAP type 1 receptor (PAC1) have been implicated in sudden infant death syndrome (SIDS). PACAP is also critical to the neonatal cardiorespiratory response to homeostatic stressors identified in SIDS, including hypoxia. However, which of PACAP’s three receptors, PAC1, vasoactive intestinal peptide receptor type 1 (VPAC1), and/or vasoactive intestinal peptide receptor type 2 (VPAC2), are involved is unknown. In this study, we hypothesized that PAC1, but not VPAC2, is involved in mediating the

APA, Harvard, Vancouver, ISO, and other styles

44

Burggren, Warren W., Gil Martinez Bautista, Susana Camarillo Coop, et al. "Developmental cardiorespiratory physiology of the air-breathing tropical gar, Atractosteus tropicus." American Journal of Physiology-Regulatory, Integrative and Comparative Physiology 311, no. 4 (2016): R689—R701. http://dx.doi.org/10.1152/ajpregu.00022.2016.

Full text

Abstract:

The physiological transition to aerial breathing in larval air-breathing fishes is poorly understood. We investigated gill ventilation frequency ( fG), heart rate ( fH), and air breathing frequency ( fAB) as a function of development, activity, hypoxia, and temperature in embryos/larvae from day (D) 2.5 to D30 posthatch of the tropical gar, Atractosteus tropicus, an obligate air breather. Gill ventilation at 28°C began at approximately D2, peaking at ∼75 beats/min on D5, before declining to ∼55 beats/min at D30. Heart beat began ∼36–48 h postfertilization and ∼1 day before hatching. fH peaked

APA, Harvard, Vancouver, ISO, and other styles

45

Greenberg, Harly E., Anthony Sica, Deirdre Batson, and Steven M. Scharf. "Chronic intermittent hypoxia increases sympathetic responsiveness to hypoxia and hypercapnia." Journal of Applied Physiology 86, no. 1 (1999): 298–305. http://dx.doi.org/10.1152/jappl.1999.86.1.298.

Full text

Abstract:

We sought to determine whether chronic exposure to intermittent hypoxia (CIH) increases sympathetic responsiveness to subsequent chemoreflex stimulation. Sprague-Dawley rats were exposed to 30 days of CIH: exposure chamber %O2 [fractional concentration of chamber O2([Formula: see text])] nadir 6.5–7% with return to 21% each minute for 8 h/day during the diurnal sleep period (Exp group). Sham controls (SC group) were similarly handled but kept at 21%[Formula: see text] and compared with unhandled controls (UC group). Rats were then anesthetized with urethan, and preganglionic cervical sympathet

APA, Harvard, Vancouver, ISO, and other styles

46

Saldívar, Enrique, Pedro Cabrales, Amy G. Tsai, and Marcos Intaglietta. "Microcirculatory changes during chronic adaptation to hypoxia." American Journal of Physiology-Heart and Circulatory Physiology 285, no. 5 (2003): H2064—H2071. http://dx.doi.org/10.1152/ajpheart.00349.2003.

Full text

Abstract:

Microcirculatory changes in the window chamber preparation in Syrian golden hamsters, secondary to chronic hypoxia adaptation, are presented herein. Adaptation was attained by keeping animals in a 10% oxygen environment for 1 wk and 5% the following week. The following groups were studied: group 1, adapted to chronic hypoxia and kept in a 5% oxygen environment throughout the experiment; group 2, adapted to chronic hypoxia and kept in a 21% oxygen environment 24 h before and during the experiment; and group 3, control. Adaptation caused venule enlargement and hematocrit increase (68.6 ± 2.44 in

APA, Harvard, Vancouver, ISO, and other styles

47

Leung, Richard S. T., John S. Floras, and T. Douglas Bradley. "Respiratory modulation of the autonomic nervous system during Cheyne–Stokes respirationThis paper is one of a selection of papers published in this Special Issue, entitled Young Investigator's Forum." Canadian Journal of Physiology and Pharmacology 84, no. 1 (2006): 61–66. http://dx.doi.org/10.1139/y05-145.

Full text

Abstract:

Cheyne–Stokes respiration (CSR) is associated with increased mortality among patients with heart failure. However, the specific link between CSR and mortality remains unclear. One possibility is that CSR results in excitation of the sympathetic nervous system. This review relates evidence that CSR exerts acute effects on the autonomic nervous system during sleep, and thereby influences a number of cardiovascular phenomena, including heart rate, blood pressure, atrioventricular conduction, and ventricular ectopy. In patients in sinus rhythm, heart rate and blood pressure oscillate during CSR in

APA, Harvard, Vancouver, ISO, and other styles

48

Curran, Aidan K., Joshua R. Rodman, Peter R. Eastwood, Kathleen S. Henderson, Jerome A. Dempsey, and Curtis A. Smith. "Ventilatory responses to specific CNS hypoxia in sleeping dogs." Journal of Applied Physiology 88, no. 5 (2000): 1840–52. http://dx.doi.org/10.1152/jappl.2000.88.5.1840.

Full text

Abstract:

Our study was concerned with the effect of brain hypoxia on cardiorespiratory control in the sleeping dog. Eleven unanesthetized dogs were studied; seven were prepared for vascular isolation and extracorporeal perfusion of the carotid body to assess the effects of systemic [and, therefore, central nervous system (CNS)] hypoxia (arterial [Formula: see text] = 52, 45, and 38 Torr) in the presence of a normocapnic, normoxic, and normohydric carotid body during non-rapid eye movement sleep. A lack of ventilatory response to systemic boluses of sodium cyanide during carotid body perfusion demonstra

APA, Harvard, Vancouver, ISO, and other styles

49

Horstick, Georg, Oliver Berg, Axel Heimann, et al. "Surgical procedure affects physiological parameters in rat myocardial ischemia: need for mechanical ventilation." American Journal of Physiology-Heart and Circulatory Physiology 276, no. 2 (1999): H472—H479. http://dx.doi.org/10.1152/ajpheart.1999.276.2.h472.

Full text

Abstract:

Several surgical approaches are being used to induce myocardial ischemia in rats. The present study investigated two different operative procedures in spontaneously breathing and mechanically ventilated rats under sham conditions. A snare around the left coronary artery (LCA) was achieved without occlusion. Left lateral thoracotomy was performed in spontaneously breathing and mechanically ventilated rats (tidal volume 8 ml/kg) with a respiratory rate of 90 strokes/min at different levels of O2 supplementation (room air and 30, 40, and 90% O2). All animals were observed for 60 min after thoraco

APA, Harvard, Vancouver, ISO, and other styles

50

Hammond, M. D., G. E. Gale, K. S. Kapitan, A. Ries, and P. D. Wagner. "Pulmonary gas exchange in humans during normobaric hypoxic exercise." Journal of Applied Physiology 61, no. 5 (1986): 1749–57. http://dx.doi.org/10.1152/jappl.1986.61.5.1749.

Full text

Abstract:

Previous studies (J. Appl. Physiol. 58: 978–988 and 989–995, 1985) have shown both worsening ventilation-perfusion (VA/Q) relationships and the development of diffusion limitation during heavy exercise at sea level and during hypobaric hypoxia in a chamber [fractional inspired O2 concentration (FIO2) = 0.21, minimum barometric pressure (PB) = 429 Torr, inspired O2 partial pressure (PIO2) = 80 Torr]. We used the multiple inert gas elimination technique to compare gas exchange during exercise under normobaric hypoxia (FIO2 = 0.11, PB = 760 Torr, PIO2 = 80 Torr) with earlier hypobaric measurement

APA, Harvard, Vancouver, ISO, and other styles

We offer discounts on all premium plans for authors whose works are included in thematic literature selections. Contact us to get a unique promo code!