Cardiorespiratory responses to physical work during and following 17 days of bed rest and spaceflight

2006 ◽  
Vol 100 (3) ◽  
pp. 951-957 ◽  
Author(s):  
Todd Trappe ◽  
Scott Trappe ◽  
Gary Lee ◽  
Jeffrey Widrick ◽  
Robert Fitts ◽  
...  

To determine the influence of a 17-day exposure to real and simulated spaceflight (SF) on cardiorespiratory function during exercise, four male crewmembers of the STS-78 space shuttle flight and eight male volunteers were studied before, during, and after the 17-day mission and 17 days of −6° head-down-tilt bed rest (BR), respectively. Measurements of oxygen uptake, pulmonary ventilation, and heart rate were made during submaximal cycling 60, 30, and 15 days before the SF liftoff and 12 and 7 days before BR; on SF days 2, 8, and 13 and on BR days 2, 8, and 13; and on days 1, 4, 5, and 8 after return to Earth and on days 3 and 7 after BR. During 15 days before liftoff, day 4 after return, and day 8 after return and all BR testing, each subject completed a continuous exercise test to volitional exhaustion on a semirecumbent (SF) or supine (BR) cycle ergometer to determine the submaximal and maximal cardiorespiratory responses to exercise. The remaining days of the SF testing were limited to a workload corresponding to 85% of the peak pre-SF peak oxygen uptake (V̇o2 peak) workload. Exposure to and recovery from SF and BR induced similar responses to submaximal exercise at 150 W. V̇o2 peak decreased by 10.4% from pre-SF (15 days before liftoff) to day 4 after return and 6.6% from pre-BR to day 3 after return, which was partially (SF: −5.2%) or fully (BR) restored within 1 wk of recovery. Workload corresponding to 85% of the peak pre-SF V̇o2 peak showed a rapid and continued decline throughout the flight (SF day 2, −6.2%; SF day 8, −9.0%), reaching a nadir of −11.3% during testing on SF day 13. During BR, V̇o2 peak also showed a decline from pre-BR (BR day 2, −7.3%; BR day 8, −7.1%; BR day 13, −9.0%). These results suggest that the onset of and recovery from real and simulated microgravity-induced cardiorespiratory deconditioning is relatively rapid, and head-down-tilt BR appears to be an appropriate model of this effect, both during and after SF.

1997 ◽  
Vol 82 (6) ◽  
pp. 1844-1852 ◽  
Author(s):  
Per-Olof Åstrand ◽  
Ulf Bergh ◽  
Åsa Kilbom

Åstrand, Per-Olof, Ulf Bergh, and Åsa Kilbom. A 33-yr follow-up of peak oxygen uptake and related variables of former physical education students. J. Appl. Physiol. 82(6): 1844–1852, 1997.—In 1949, 27 female and 26 male physical education students were studied at a mean age of 22 and 25 yr, respectively. They were restudied in 1970 and 1982. Measurements included oxygen uptake, heart rate, and pulmonary ventilation during submaximal and maximal exercise on a cycle ergometer and treadmill. After 21 yr, peak aerobic power was significantly reduced, from 2.90 to 2.18 l/min and from 4.09 to 3.28 l/min for women and men, respectively. After another 12 yr, the 1970 maxima were not reduced further. From 1949 to 1982 there was a decrease in peak heart rate from 196 to 177 beats/min in women and from 190 to 175 beats/min in men ( P < 0.05). Highest pulmonary ventilation did not change significantly. At an oxygen uptake of 1.5 l/min, the heart rate was the same in 1949 as in 1982. In conclusion, the physical fitness level of the subjects was well above average for these ages. From 1970 to 1982 there was no decline in the average peak aerobic power, a finding possibly related to increased habitual physical activity.


1980 ◽  
Vol 48 (6) ◽  
pp. 1060-1064 ◽  
Author(s):  
R. M. Glaser ◽  
M. N. Sawka ◽  
M. F. Brune ◽  
S. W. Wilde

The purpose of this investigation was to compare physical work capacity (PWC), peak oxygen uptake (peak VO2), maximal pulmonary ventilation (VEmax), maximal heart rate (HRmax), and maximal blood lactate concentration (LAmax) for wheelchair ergometer (WERG) and arm crank ergometer (ACE) exercise. For this, wheelchair-dependent (n = 6) and able-bodied (n = 10) subjects completed a progressive intensity, discontinuous test for each mode of exercise. Each test was terminated by physical exhaustion and/or an inability to maintain a flywheel velocity of 180 m.min-1. Relatively high correlation coefficients were found between values obtained during the two modes of ergometry for PWC, peak VO2, VEmax, and HRmax. WERG exercise was found to elicit a significantly (P less than 0.05) lower PWC (by 36%), HRmax (by 7%), and LAmax (by 26%) than ACE exercise. Peak VO2 and VEmax, however, were similar for both exercise modes. These data suggest that either exercise mode may be used for fitness testing and training of people who cannot use their legs and that arm cranking may be a superior method to propel wheelchairs.


1982 ◽  
Vol 14 (6) ◽  
pp. 477???480
Author(s):  
JOHN E. GREENLEAF ◽  
STANISLAW KOZLOWSKI

2015 ◽  
Vol 40 (4) ◽  
pp. 379-385 ◽  
Author(s):  
Roksana B. Zak ◽  
Clayton L. Camic ◽  
Ethan C. Hill ◽  
Molly M. Monaghan ◽  
Attila J. Kovacs ◽  
...  

The purpose of the present study was to examine the effects of an acute dose of an arginine-based supplement on the physical working capacity at the fatigue threshold (PWCFT), lactate threshold (LT), ventilatory threshold (VT), and peak oxygen uptake during incremental cycle ergometry. This study used a double-blinded, placebo-controlled, within-subjects crossover design. Nineteen untrained men (mean age ± SD = 22.0 ± 1.7 years) were randomly assigned to ingest either the supplement (3.0 g of arginine, 300 mg of grape seed extract, and 300 mg of polyethylene glycol) or placebo (microcrystalline cellulose) and performed an incremental test on a cycle ergometer for determination of PWCFT, LT, VT, and peak oxygen uptake. Following a 1-week period, the subjects returned to the laboratory and ingested the opposite substance (either supplement or placebo) prior to completing another incremental test to be reassessed for PWCFT, LT, VT, and peak oxygen uptake. The paired-samples t tests indicated there were significant (P < 0.05) mean differences between the arginine and placebo conditions for the PWCFT (192 ± 42 vs. 168 ± 53 W, respectively) and VT (2546 ± 313 vs. 2452 ± 342 mL·min−1), but not the LT (135 ± 26 vs. 138 ± 22 W), absolute peak oxygen uptake (3663 ± 445 vs. 3645 ± 438 mL·min−1), or relative peak oxygen uptake (46.5 ± 6.0 vs. 46.2 ± 5.0 mL·kg−1·min−1). These findings suggested that the arginine-based supplement may be used on an acute basis for delaying the onset of neuromuscular fatigue (i.e., PWCFT) and improving the VT in untrained individuals.


2014 ◽  
Vol 94 (1) ◽  
pp. 121-128 ◽  
Author(s):  
Merel-Anne Brehm ◽  
Astrid C.J. Balemans ◽  
Jules G. Becher ◽  
Annet J. Dallmeijer

BackgroundRehabilitation research in children with cerebral palsy (CP) is increasingly addressing cardiorespiratory fitness testing. However, evidence on the reliability of peak oxygen uptake (V̇o2peak) measurements, considered the best indicator of aerobic fitness, is not available in this population.ObjectiveThe objective of this study was to establish the reliability of a progressive maximal cycle ergometer test when assessing V̇o2peak in children with mild to moderate CP.DesignRepeated measures were used to assess test-retest reliability.MethodsEligible participants were ambulant, 6 to 14 years of age, and classified as level I, II, or III according to the Gross Motor Function Classification System (GMFCS). Two progressive maximal cycle ergometer tests were conducted (separated by 3 weeks), with the workload increasing every minute in steps of 3 to 11 W, dependent on height and GMFCS level. Reliability was determined by means of the intraclass correlation coefficient (ICC [2,1]) and smallest detectable change (SDC).ResultsTwenty-one children participated (GMFCS I: n=4; GMFCS II: n=12; and GMFCS III: n=5). Sixteen of them (9 boys, 7 girls; GMFCS I: n=3; GMFCS II: n=11; and GMFCS III: n=2) performed 2 successful tests, separated by 9.5 days on average. Reliability for V̇o2peak was excellent (ICC=.94, 95% confidence interval=.83–.98). The SDC was 5.72 mL/kg/min, reflecting 14.6% of the mean.LimitationsThe small sample size did not allow separate analysis of reliability per GMFCS level.ConclusionsIn children with CP of GMFCS levels I and II, a progressive maximal cycle ergometer test to assess V̇o2peak is reliable and has the potential to detect change in cardiorespiratory fitness over time. Further study is needed to establish the reliability of V̇o2peak in children of GMFCS level III.


2022 ◽  
Vol 15 (1) ◽  
Author(s):  
Peter Düking ◽  
Philipp Kunz ◽  
Florian A. Engel ◽  
Helena Mastek ◽  
Billy Sperlich

Abstract Objective Portable gas exchange instruments allow the assessment of peak oxygen uptake (V̇O2peak) but are often bulky, expensive and require wearing a face mask thereby limiting their routine application. A newly developed miniaturized headset (VitaScale, Nuremberg, Germany) may overcome these barriers and allow measuring V̇O2peak without applying a face mask. Here we aimed (i) to disclose the technical setup of a headset incorporating a gas and volume sensor to measure volume flow and expired oxygen concentration and (ii) to assess the concurrent criterion-validity of the headset to measure V̇O2peak in 44 individuals exercising on a stationary cycle ergometer in consideration of the test–retest reliability of the criterion measure. Results The coefficient of variation (CV%) while measuring V̇O2peak during incremental cycling with the headset was 6.8%. The CV% for reliability of the criterion measure was 4.0% for V̇O2peak. Based on the present data, the headset might offer a new technology for V̇O2peak measurement due to its low-cost and mask-free design.


1982 ◽  
Vol 14 (6) ◽  
pp. 477-480 ◽  
Author(s):  
JOHN E. GREENLEAF ◽  
STANISLAW KOZLOWSKI

2017 ◽  
Vol 42 (4) ◽  
pp. 371-376 ◽  
Author(s):  
Rafał Hebisz ◽  
Paulina Hebisz ◽  
Marek Zatoń ◽  
Kamil Michalik

In the literature, the exercise capacity of cyclists is typically assessed using incremental and endurance exercise tests. The aim of the present study was to confirm whether peak oxygen uptake (V̇O2peak) attained in a sprint interval testing protocol correlates with cycling performance, and whether it corresponds to maximal oxygen uptake (V̇O2max) determined by an incremental testing protocol. A sample of 28 trained mountain bike cyclists executed 3 performance tests: (i) incremental testing protocol (ITP) in which the participant cycled to volitional exhaustion, (ii) sprint interval testing protocol (SITP) composed of four 30 s maximal intensity cycling bouts interspersed with 90 s recovery periods, (iii) competition in a simulated mountain biking race. Oxygen uptake, pulmonary ventilation, work, and power output were measured during the ITP and SITP with postexercise blood lactate and hydrogen ion concentrations collected. Race times were recorded. No significant inter-individual differences were observed in regards to any of the ITP-associated variables. However, 9 individuals presented significantly increased oxygen uptake, pulmonary ventilation, and work output in the SITP compared with the remaining cyclists. In addition, in this group of 9 cyclists, oxygen uptake in SITP was significantly higher than in ITP. After the simulated race, this group of 9 cyclists achieved significantly better competition times (99.5 ± 5.2 min) than the other cyclists (110.5 ± 6.7 min). We conclude that mountain bike cyclists who demonstrate higher peak oxygen uptake in a sprint interval testing protocol than maximal oxygen uptake attained in an incremental testing protocol demonstrate superior competitive performance.


PLoS ONE ◽  
2015 ◽  
Vol 10 (2) ◽  
pp. e0117563 ◽  
Author(s):  
Camila D. C. Neves ◽  
Ana Cristina Rodrigues Lacerda ◽  
Vanessa K. S. Lage ◽  
Liliana P. Lima ◽  
Sueli F. Fonseca ◽  
...  

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