Cardiorespiratory Response and Power Output During Submaximal Exercise in Normobaric Versus Hypobaric Hypoxia: A Pilot Study Using a Specific Chamber that Controls Environmental Factors

2021 ◽  
Author(s):  
Toshihiro Takezawa ◽  
Shohei Dobashi ◽  
Katsuhiro Koyama
Keyword(s):  
Pilot Study ◽  
Environmental Factors ◽  
Power Output ◽  
Hypobaric Hypoxia ◽  
Submaximal Exercise ◽  
Cardiorespiratory Response

Cardiorespiratory Response and Power Output During Submaximal Exercise in Normobaric Versus Hypobaric Hypoxia: A Pilot Study Using a Specific Chamber that Controls Environmental Factors

Impact ◽  
2021 ◽  
Vol 2021 (8) ◽  
pp. 55-57
Author(s):  
Toshihiro Takezawa ◽  
Shohei Dobashi ◽  
Katsuhiro Koyama
Keyword(s):  
Environmental Factors ◽  
Power Output ◽  
High Intensity ◽  
Hypobaric Hypoxia ◽  
Atmospheric Oxygen ◽  
Physiological Responses ◽  
Barometric Pressure ◽  
High Intensity Exercise ◽  
Fraction Of Inspired Oxygen ◽  
Inspired Oxygen

2021.—Many previous studies have examined hypoxia-induced physiological responses using various conditions, e.g., artificially reduced atmospheric oxygen concentration [normobaric hypoxia (NH) condition] or low barometric pressure at a mountain [hypobaric hypoxia (HH) condition]. However, when comparing the results from these previous studies conducted in artificial NH and HH including real high altitude, we must consider the possibility that environmental factors, such as temperature, humidity, and fraction of inspired carbon dioxide, might affect the physiological responses. Therefore, we examined cardiorespiratory responses and exercise performances during low- to high-intensity exercise at a fixed heart rate (HR) in both NH and HH using a specific chamber where atmospheric oxygen concentration and barometric pressure as well as the abovementioned environmental factors were precisely controlled. Ten well-trained university students (eight males and two females) performed the exercise test consisting of two 20-minute submaximal pedaling at the intensity corresponding to 50% (low) and 70% (high) of their HR reserve, under three conditions [NH (fraction of inspired oxygen, 0.135; barometric pressure, 754 mmHg), HH (fraction of inspired oxygen, 0.209; barometric pressure, 504 mmHg), and normobaric normoxia (NN; fraction of inspired oxygen, 0.209; barometric pressure, 754 mmHg)]. Peripheral oxygen saturation (SpO2) to estimate arterial oxygen saturation and partial pressure of end-tidal carbon dioxide (PETCO2) were monitored throughout the experiment. SpO2, PETCO2, and power output at fixed HRs (i.e., pedaling efficiency) in NH and HH were all significantly lower than those in NN. Moreover, high-intensity exercise in HH induced greater decreases in SpO2 and power output than did high-intensity exercise in NH (NH vs. HH; SpO2, 78.2% - 5.0% vs. 75.1% - 7.1%; power output, 120.7 - 24.9 W vs. 112.4 - 23.2 W, both p < 0.05). However, high-intensity exercise in HH induced greater increases in PETCO2 than did high-intensity exercise in NH (NH vs. HH; 54.2 - 5.9mmHg vs. 57.2 - 3.4 mmHg, p < 0.01). These results suggest that physiological responses and power output at a fixed HR during hypoxic exposure might depend on the method used to generate the hypoxic condition.

scholarly journals A pilot study on left ventricular dimensions and wall stress before and after submaximal exercise.

1979 ◽  
Vol 13 (3) ◽  
pp. 122-129 ◽  
Author(s):  
N. S. Cahill ◽  
M. O'Brien ◽  
A. Rodahl ◽  
J. F. Allen ◽  
D. Knight ◽  
...  
Keyword(s):  
Pilot Study ◽  
Wall Stress ◽  
Left Ventricular ◽  
Submaximal Exercise ◽  
Before And After ◽  
Left Ventricular Dimensions ◽  
Ventricular Dimensions

Early Environmental Factors for Atopic Dermatitis in Children: Pilot Study of Taiwan Birth Cohort Study (TBCS)

Epidemiology ◽  
2006 ◽  
Vol 17 (Suppl) ◽  
pp. S230-S231
Author(s):  
H J. Wen ◽  
Y C. Lin ◽  
Y L. Lee ◽  
S J. Lin ◽  
Y L. Chiang ◽  
...  
Keyword(s):  
Atopic Dermatitis ◽  
Cohort Study ◽  
Pilot Study ◽  
Environmental Factors ◽  
Birth Cohort ◽  
Birth Cohort Study ◽  
Taiwan Birth Cohort Study

Increases in submaximal cycling efficiency mediated by altitude acclimatization

2000 ◽  
Vol 89 (3) ◽  
pp. 1189-1197 ◽  
Author(s):  
H. J. Green ◽  
B. Roy ◽  
S. Grant ◽  
R. Hughson ◽  
M. Burnett ◽  
...  
Keyword(s):  
Sea Level ◽  
Power Output ◽  
Minute Ventilation ◽  
Hemoglobin Concentration ◽  
Submaximal Exercise ◽  
Step Cycle ◽  
Exercise Tests ◽  
Cycling Efficiency ◽  
Mechanical Power Output ◽  
Response To Exercise

To investigate the hypothesis that respiratory gas exchange and, in particular, the O2 consumption (V˙o 2) response to exercise is altered after a 21-day expedition to 6,194 m, five male climbers (age 28.2 ± 2 yr; weight 76.9 ± 4.3 kg; means ± SE) performed a progressive and prolonged two-step cycle test both before and 3–4 days after return to sea level. During both exercise tests, a depression ( P < 0.05) inV˙o 2 (l/min) and an increase ( P < 0.05) in minute ventilation (V˙e btps; l/min) and respiratory exchange ratio were observed after the expedition. These changes occurred in the absence of changes in CO2 production (l/min). During steady-state submaximal exercise, net efficiency, calculated from the rates of the mechanical power output to the energy expended (V˙o 2) above that measured at rest, increased ( P < 0.05) from 25.9 ± 1.6 to 31.3 ± 1.3% at the lighter power output and from 24.4 ± 1.3 to 29.5 ± 1.5% at the heavy power output. These changes were accompanied by a 4.5% reduction ( P< 0.05) in peak V˙o 2 (3.99 ± 0.17 vs. 3.81 ± 0.18 l/min). After the expedition, an increase ( P < 0.05) in hemoglobin concentration (15.0 ± 0.49 vs. 15.8 ± 0.41 g/100 ml) was found. It is concluded that, because resting V˙o 2 was unchanged, net efficiency is enhanced during submaximal exercise after a mountaineering expedition when the exercise is performed soon after return to sea level conditions.

Impact of autism-associated genetic variants in interaction with environmental factors on ADHD comorbidities: an exploratory pilot study

2019 ◽  
Vol 126 (12) ◽  
pp. 1679-1693
Author(s):  
Regina Waltes ◽  
Christine M. Freitag ◽  
Timo Herlt ◽  
Thomas Lempp ◽  
Christiane Seitz ◽  
...  
Keyword(s):  
Pilot Study ◽  
Environmental Factors ◽  
Genetic Variants

Reliability of Fitness Measures in 3- to 5-Year-Old Children

2011 ◽  
Vol 23 (2) ◽  
pp. 250-260 ◽  
Author(s):  
Thanh Nguyen ◽  
Joyce Obeid ◽  
Brian W. Timmons
Keyword(s):  
Heart Rate ◽  
Preschool Children ◽  
Power Output ◽  
Coefficient Of Variation ◽  
Intraclass Correlation ◽  
Submaximal Exercise ◽  
Treadmill Test ◽  
Short Term ◽  
Fitness Tests ◽  
Fitness Measures

The purpose of this study was to determine the reliability of short-term power output, heart rate (HR) response during and after a treadmill test, and time to complete a 25-m dash in healthy preschool children. Thirty-two 3- to 5-year-old boys and girls completed two sessions approximately one week apart. Intraclass correlation coefficient (ICC) and coefficient of variation (CV) were calculated to evaluate reliability. Power output was found to be reliable with ICCs ranging from 0.83 to 0.93 and CVs from 8.1 to 9.7%. Time to complete the 25-m dash was highly reliable (ICC = 0.91, CV = 3.7%). Reliability for HR at submaximal exercise (ICC = 0.28, CV = 18.8%) and HR recovery (ICC = 0.42, CV = 14.0%) was not as strong. These findings should assist in determining appropriate fitness tests for preschoolers.

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