Cardiorespiratory Responses of Adults and Children during Normoxic and Hypoxic Exercise

2017 ◽  
Vol 38 (08) ◽  
pp. 627-636 ◽  
Author(s):  
Jernej Kapus ◽  
Igor Mekjavic ◽  
Adam McDonnell ◽  
Anton Ušaj ◽  
Janez Vodičar ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Minute Ventilation ◽  
Group Differences ◽  
Cycling Test ◽  
Cardiorespiratory Responses ◽  
Adults And Children ◽  
Low Altitude ◽  
Hypoxic Acclimation ◽  
Hypoxic Exercise

AbstractWe aimed to elucidate potential differential effects of hypoxia on cardiorespiratory responses during submaximal cycling and simulated skiing exercise between adults and pre-pubertal children. Healthy, low-altitude residents (adults, N=13, Age=40±4yrs.; children, N=13, age=8±2yrs.) were tested in normoxia (Nor: PiO2=134±0.4 mmHg; 940 m) and normobaric hypoxia (Hyp: PiO2=105±0.6 mmHg; ~3 000 m) following an overnight hypoxic acclimation (≥12-hrs). On both days, the participants underwent a graded cycling test and a simulated skiing protocol. Minute ventilation (VE), oxygen uptake (VO2), heart rate (HR) and capillary-oxygen saturation (SpO2) were measured throughout both tests. The cycling data were interpolated for 2 relative workload levels (1 W·kg−1 & 2 W·kg−1). Higher resting HR in hypoxia, compared to normoxia was only noted in children (Nor:78±17; Hyp:89±17 beats·min−1; p<0.05), while SpO2 was significantly lower in hypoxia (Nor:97±1%; Hyp:91±2%; p<0.01) with no between-group differences. The VE, VO2 and HR responses were higher during hypoxic compared to normoxic cycling test in both groups (p<0.05). Except for greater HR during hypoxic compared to normoxic skiing in children (Nor:155±19; Hyp:167±13 (beats·min−1); p<0.05), no other significant between-group differences were noted during the cycling and skiing protocols. In summary, these data suggest similar cardiorespiratory responses to submaximal hypoxic cycling and simulated skiing in adults and children.

Cardiorespiratory responses during prolonged exercise

1961 ◽  
Vol 16 (6) ◽  
pp. 997-1000 ◽  
Author(s):  
Ernest D. Michael ◽  
Kenneth E. Hutton ◽  
Steven M. Horvath
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Energy Cost ◽  
Prolonged Exercise ◽  
Bicycle Ergometer ◽  
Maximum Oxygen Uptake ◽  
Healthy Male ◽  
Heart Rates ◽  
Cardiorespiratory Responses ◽  
Male Subjects

Three healthy male subjects 20 years of age were exercised for 2—8 hr riding a bicycle ergometer or walking on a treadmill. Higher heart rates were found with the bicycle rides than with the walking exercises with equivalent oxygen uptakes. The subjects could not work on the bicycle ergometer at oxygen uptakes of 1.8 liters/min for more than 4 hr but could with this uptake walk 8 hr. The results indicated that an 8-hr period of exercise could be completed without undue fatigue whenever the energy cost did not exceed 35% of the maximum oxygen uptake where heart rates, oxygen uptakes, and rectal temperatures remained below 120 beats/min, 1.4 liters/min, and 38 C, respectively. The heart rate appeared to be the important factor for estimating 8-hr work endurance. A rate of 140 beats/min could not be maintained for more than 4 hr or a rate of 160 beats/min for more than 2 hr without extreme fatigue. Submitted on October 26, 1960

scholarly journals Oxygen uptake and heart rate responses during hypoxic exercise in children and adults

1991 ◽  
Vol 23 (1) ◽  
pp. 71???79 ◽  
Author(s):  
CHAIM SPRINGER ◽  
THOMAS J. BARSTOW ◽  
KARLMAN WASSERMAN ◽  
DAN M. COOPER
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Hypoxic Exercise

scholarly journals Estimation of energy expenditure of Nordic walking: a crossover trial

2021 ◽  
Vol 13 (1) ◽  
Author(s):  
Sora Baek ◽  
Yuncheol Ha
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Systolic Blood Pressure ◽  
Lower Limb ◽  
Surface Electromyography ◽  
Minute Ventilation ◽  
Lower Limb Muscles ◽  
Limb Muscles

Abstract Background Nordic walking (NW) requires more energy compared with conventional walking (W). However, the metabolic equation for NW has not been reported. Therefore, this study aimed to characterize responses in oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography of the upper and lower limb muscles during NW and W and develop a metabolic equation for energy expenditure (E, mL·kg− 1·min− 1) of NW. Methods This study was performed in a randomized, controlled, crossover design to test the energy expenditure during NW and W. Fifteen healthy young men were enrolled (aged 23.7 ± 3.0 years). All participants performed two randomly ordered walking tests (NW and W) on a treadmill at a predetermined stepwise incremental walking speed (3–5 km·h− 1) and grade (0–7%). The oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography signals of the three upper limb muscles and three lower limb muscles in their right body were recorded and compared between NW and W using paired-t test. Multiple linear regression analysis was used to draw estimation of E during W and NW. Results Oxygen uptake (+ 15.8%), minute ventilation (+ 17.0%), heart rate (+ 8.4%), and systolic blood pressure (+ 7.7%) were higher in NW than in W (P < .05). NW resulted in increased muscle activity in all of the upper limb muscles (P < .05). In the lower limb, surface electromyography activities in two of the three lower limb muscles were increased in NW than in W only during level walking (P < .05). Energy expenditure during W and NW was estimated as follows: ENW = 6.1 + 0.09 × speed + 1.19 × speed × grade and EW = 4.4 + 0.09 × speed + 1.20 × speed × grade. Conclusion NW showed higher work intensity than W, with an oxygen consumption difference of 1.7 mL·kg− 1·min− 1. The coefficients were not different between the two walking methods. NW involved more muscles of the upper body than W.

Arterial Catecholamines in Hypoxic Exercise in Man

1975 ◽  
Vol 49 (5) ◽  
pp. 503-506 ◽  
Author(s):  
L. J. Clancy ◽  
J. A. J. H. Critchley ◽  
A. G. Leitch ◽  
B. J. Kirby ◽  
A. Ungar ◽  
...  
Keyword(s):  
Oxygen Uptake ◽  
Treadmill Exercise ◽  
Minute Ventilation ◽  
Plasma Noradrenaline ◽  
Moderate Exercise ◽  
Respiratory Response ◽  
Arterial Blood ◽  
Arterial Plasma ◽  
Normal Men ◽  
Hypoxic Exercise

1. We measured the minute ventilation and arterial blood catecholamine concentrations in four normal men standing and at two levels of moderate treadmill exercise breathing 14% oxygen or air. 2. Minute ventilation was significantly higher during hypoxic exercise than during normoxic exercise at an oxygen uptake of 1500 ml/min. 3. Arterial plasma noradrenaline during hypoxic exercise at an oxygen uptake of 1500 ml/min was significantly greater than at rest. 4. Arterial plasma noradrenaline during normoxic exercise at an oxygen uptake of 1500 ml/min was not elevated above the resting concentration. 5. The results are compatible with the suggestion that increased concentrations of arterial plasma noradrenaline contribute to the hypoxic potentiation of the respiratory response to moderate exercise.

Faster oxygen uptake, heart rate, and ventilatory kinetics in stepping compared with cycle ergometry in patients with COPD during moderate-intensity exercise

2019 ◽  
Vol 44 (8) ◽  
pp. 879-885 ◽  
Author(s):  
Paulo de Tarso Müller ◽  
João Henrique Zardetti Nogueira ◽  
Tiago Rodrigues de Lemos Augusto ◽  
Gaspar Rogério Chiappa
Keyword(s):  
Heart Rate ◽  
Steady State ◽  
Oxygen Uptake ◽  
Minute Ventilation ◽  
Cycle Ergometry ◽  
Aerobic Performance ◽  
Moderate Intensity ◽  
Chronic Obstructive ◽  
Moderate Intensity Exercise ◽  
Time Constants

Step tests are a stressful and feasible cost-effective modality to evaluate aerobic performance. However, the eccentric in addition to concentric muscle contractions of the legs on stepping emerge as a potential speeding factor for cardioventilatory and metabolic adjustments towards a steady-state, since eccentric contractions would prompt an earlier and stronger mechanoreceptor activation, as well as higher heart rate/cardiac output adjustments to the same metabolic demand. Moreover, shorter tests are ideal for exercise-limited subjects. Nine subjects with chronic obstructive pulmonary disease were invited to participate in comprehensive lung function tests and constant work tests performed on different days at a 90% gas exchange threshold for 6 min, in single-step tests or cycle ergometry. After careful monoexponential regression modelling, statistically relevant faster phase II time constants for oxygen uptake (45 ± 18 s vs 53 ± 17 s, p = 0.017) and minute ventilation (61 ± 13 s vs 74 ± 17 s, p = 0.027) were observed in the 6-min step tests compared with cycle ergometry, respectively. Despite an absence of heart rate time constant difference (43 ± 20 s vs 69 ± 46 s, p = 0.167), there was a significantly faster rate constant toward a steady state for heart rate (p = 0.02). In addition, 4-min compared with 6-min analysis presented similar results (p > 0.05), providing an appropriate steady-state. We conclude that step tests might elicit faster time constants compared with cycle ergometry, at the same average metabolic level, and 4-min analysis has similar mean errors compared with 6-min analysis within an acceptable range. New studies, comprising mechanisms and detailed physiological backgrounds, are necessary.

Impaired cardiorespiratory responses to hypercapnia in neonatal mice lacking PAC1 but not VPAC2 receptors

2020 ◽  
Author(s):  
Karlene T. Barrett ◽  
Shabih U. Hasan ◽  
Morris H. Scantlebury ◽  
Richard J.A. Wilson
Keyword(s):  
Heart Rate ◽  
Heart Rate Recovery ◽  
Minute Ventilation ◽  
Sudden Infant Death ◽  
Sudden Infant ◽  
Pac1 Receptor ◽  
Childhood Disorders ◽  
Cardiorespiratory Responses ◽  
Surface Ecg ◽  
Spontaneously Breathing

The evidence is mounting for a role for abnormal signaling of the stress peptide, pituitary adenylate cyclase activating polypeptide (PACAP), and its canonical receptor, PAC1, in the pathogenesis of sudden infant death syndrome (SIDS). In this study, we investigated whether the PACAP receptors, PAC1 or VPAC2, are involved in the neonatal cardiorespiratory response to hypercapnic stress. We used head-out plethysmography and surface ECG electrodes to assess cardiorespiratory responses to an 8% hypercapnic challenge in unanesthetized and spontaneously breathing 4 days old PAC1 or VPAC2 knockout (KO) and wildtype (WT) mouse pups. We demonstrate that compared to WTs, breathing frequency (RR) and minute ventilation () in PAC1 KO pups were significantly blunted in response to hypercapnia. Although heart rate was unaltered in PAC1 KO pups during hypercapnia, heart rate recovery post-hypercapnia was impaired. In contrast, cardiorespiratory impairments in VPAC2 KO pups were limited to only an overall higher tidal volume (VT), independent of treatment. These findings suggest that PACAP signaling through the PAC1 receptor plays a more important role than signaling through the VPAC2 receptor, in neonatal respiratory responses to hypercapnia. Thus, deficits in PACAP signaling primarily via PAC1 may contribute to the inability of infants to mount an appropriate protective response to homeostatic stressors in childhood disorders such as SIDS.

scholarly journals A Focused Review on the Maximal Exercise Responses in Hypo- and Normobaric Hypoxia: Divergent Oxygen Uptake and Ventilation Responses

2020 ◽  
Vol 17 (14) ◽  
pp. 5239 ◽  
Author(s):  
Benedikt Treml ◽  
Hannes Gatterer ◽  
Johannes Burtscher ◽  
Axel Kleinsasser ◽  
Martin Burtscher
Keyword(s):  
Oxygen Uptake ◽  
Athletic Training ◽  
Exercise Test ◽  
Minute Ventilation ◽  
Arterial Oxygen Saturation ◽  
Treadmill Running ◽  
Arterial Oxygen ◽  
Limited Information ◽  
Exercise Tests ◽  
Cardiorespiratory Responses

The literature suggests that acute hypobaric (HH) and normobaric (NH) hypoxia exposure elicits different physiological responses. Only limited information is available on whether maximal cardiorespiratory exercise test outcomes, performed on either the treadmill or the cycle ergometer, are affected differently by NH and HH. A focused literature review was performed to identify relevant studies reporting cardiorespiratory responses in well-trained male athletes (individuals with a maximal oxygen uptake, VO2max > 50 mL/min/kg at sea level) to cycling or treadmill running in simulated acute HH or NH. Twenty-one studies were selected. The exercise tests in these studies were performed in HH (n = 90) or NH (n = 151) conditions, on a bicycle ergometer (n = 178) or on a treadmill (n = 63). Altitudes (simulated and terrestrial) varied between 2182 and 5400 m. Analyses (based on weighted group means) revealed that the decline in VO2max per 1000 m gain in altitude was more pronounced in acute NH vs. HH (−7.0 ± 1.4% vs. −5.6 ± 0.9%). Maximal minute ventilation (VEmax) increased in acute HH but decreased in NH with increasing simulated altitude (+1.9 ± 0.9% vs. −1.4 ± 1.8% per 1000 m gain in altitude). Treadmill running in HH caused larger decreases in arterial oxygen saturation and heart rate than ergometer cycling in acute HH, which was not the case in NH. These results indicate distinct differences between maximal cardiorespiratory responses to cycling and treadmill running in acute NH or HH. Such differences should be considered when interpreting exercise test results and/or monitoring athletic training.

scholarly journals Strength Training Prior to Endurance Exercise: Impact on the Neuromuscular System, Endurance Performance and Cardiorespiratory Responses

2014 ◽  
Vol 44 (1) ◽  
pp. 171-181 ◽  
Author(s):  
Matheus Conceição ◽  
Eduardo Lusa Cadore ◽  
Miriam González-Izal ◽  
Mikel Izquierdo ◽  
Giane Veiga Liedtke ◽  
...  
Keyword(s):  
Heart Rate ◽  
Oxygen Uptake ◽  
Strength Training ◽  
Endurance Exercise ◽  
Maximal Voluntary Contraction ◽  
Endurance Performance ◽  
Voluntary Contraction ◽  
Force Development ◽  
Cardiorespiratory Responses ◽  
Training Protocol

Abstract This study aimed to investigate the acute effects of two strength-training protocols on the neuromuscular and cardiorespiratory responses during endurance exercise. Thirteen young males (23.2 ± 1.6 years old) participated in this study. The hypertrophic strength-training protocol was composed of 6 sets of 8 squats at 75% of maximal dynamic strength. The plyometric strength-training protocol was composed of 6 sets of 8 jumps performed with the body weight as the workload. Endurance exercise was performed on a cycle ergometer at a power corresponding to the second ventilatory threshold until exhaustion. Before and after each protocol, a maximal voluntary contraction was performed, and the rate of force development and electromyographic parameters were assessed. After the hypertrophic strengthtraining and plyometric strength-training protocol, significant decreases were observed in the maximal voluntary contraction and rate of force development, whereas no changes were observed in the electromyographic parameters. Oxygen uptake and a heart rate during endurance exercise were not significantly different among the protocols. However, the time-to-exhaustion was significantly higher during endurance exercise alone than when performed after hypertrophic strength-training or plyometric strength-training (p <0.05). These results suggest that endurance performance may be impaired when preceded by strength-training, with no oxygen uptake or heart rate changes during the exercise.

scholarly journals Estimation of Energy Expenditure of Nordic Walking: A Crossover Trial

2020 ◽  
Author(s):  
Sora Baek ◽  
Yuncheol Ha
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Systolic Blood Pressure ◽  
Lower Limb ◽  
Surface Electromyography ◽  
Minute Ventilation ◽  
Lower Limb Muscles ◽  
Limb Muscles

Abstract Background: Nordic walking (NW) requires more energy compared with conventional walking (W). However, the metabolic equation for NW has not been reported. Therefore, this study aimed to characterize responses in oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography of the upper and lower limb muscles during NW and W and develop a metabolic equation for energy expenditure (E, mL·kg-1·min-1) of NW.Methods: This study was performed in a randomized, controlled, crossover design to test the energy expenditure during NW and W. Fifteen healthy young men were enrolled (aged 23.7 ± 3.0 years). All participants performed two randomly ordered walking tests (NW and W) on a treadmill at a predetermined stepwise incremental walking speed (3–5 km·h-1) and grade (0%–7%). The oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography signals of the three upper limb muscles and three lower limb muscles in their right body were recorded and compared between NW and W using paired-t test. Multiple linear regression analysis was used to draw estimation of E during W and NW.Results: Oxygen uptake (+15.8%), minute ventilation (+17.0%), heart rate (+8.4%), and systolic blood pressure (+7.7%) were higher in NW than in W (P<.05). NW resulted in increased muscle activity in all of the upper limb muscles (P<.05). In the lower limb, surface electromyography activities in two of the three lower limb muscles were increased in NW than in W only during level walking (P<.05). Energy expenditure during W and NW was estimated as follows: ENW = 6.1 + 0.09 × speed + 1.19 × speed × grade and EW = 4.4 + 0.09 × speed + 1.20 × speed × grade.Conclusion: NW showed higher work intensity than W, with an oxygen consumption difference of 1.7 mL·kg-1·min-1. The coefficients were not different between the two walking methods. NW involved more muscles of the upper body than W.

scholarly journals Estimation of Energy Expenditure of Nordic Walking: A Crossover Trial

2021 ◽  
Author(s):  
Sora Baek ◽  
Yuncheol Ha
Keyword(s):  
Blood Pressure ◽  
Heart Rate ◽  
Energy Expenditure ◽  
Oxygen Uptake ◽  
Systolic Blood Pressure ◽  
Lower Limb ◽  
Surface Electromyography ◽  
Minute Ventilation ◽  
Lower Limb Muscles ◽  
Limb Muscles

Abstract Background: Nordic walking (NW) requires more energy compared with conventional walking (W). However, the metabolic equation for NW has not been reported. Therefore, this study aimed to characterize responses in oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography of the upper and lower limb muscles during NW and W and develop a metabolic equation for energy expenditure (E, mL·kg-1·min-1) of NW.Methods: This study was performed in a randomized, controlled, crossover design to test the energy expenditure during NW and W. Fifteen healthy young men were enrolled (aged 23.7 ± 3.0 years). All participants performed two randomly ordered walking tests (NW and W) on a treadmill at a predetermined stepwise incremental walking speed (3–5 km·h-1) and grade (0%–7%). The oxygen uptake, minute ventilation, heart rate, systolic blood pressure, and surface electromyography signals of the three upper limb muscles and three lower limb muscles in their right body were recorded and compared between NW and W using paired-t test. Multiple linear regression analysis was used to draw estimation of E during W and NW.Results: Oxygen uptake (+15.8%), minute ventilation (+17.0%), heart rate (+8.4%), and systolic blood pressure (+7.7%) were higher in NW than in W (P<.05). NW resulted in increased muscle activity in all of the upper limb muscles (P<.05). In the lower limb, surface electromyography activities in two of the three lower limb muscles were increased in NW than in W only during level walking (P<.05). Energy expenditure during W and NW was estimated as follows: ENW = 6.1 + 0.09 × speed + 1.19 × speed × grade and EW = 4.4 + 0.09 × speed + 1.20 × speed × grade.Conclusion: NW showed higher work intensity than W, with an oxygen consumption difference of 1.7 mL·kg-1·min-1. The coefficients were not different between the two walking methods. NW involved more muscles of the upper body than W.

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