Abstract
Purpose
Heart rate (HR), pulmonary and muscle oxygen uptake (˙VO2pulm, ˙VO2musc) kinetics after changes of work rate (WR) indicate regulatory characteristics related to aerobic metabolism. We analysed whether the kinetics of HR, ˙VO2pulm and ˙VO2musc are slowed after missions to the International Space Station (ISS). The changes of the kinetics were correlated with ˙VO2peak data.
Methods
10 astronauts [4 females, 6 males, age: 48.0 ± 3.8 years, height: 176 ± 7 cm, mass: 74.5 ± 15.9 kg (mean ± SD)] performed an incremental test to determine ˙VO2peak (before missions on L-110 days, after return on R+1/+10/+36 days), and a cardio-respiratory kinetics test (CRKT) with randomized 30–80 W WR changes to determine HR, ˙VO2pulm and ˙VO2musc kinetics by time-series analysis (L-236/-73, R+6/+21). Kinetics were summarized by maximum and related lag of cross-correlation function (CCFmax, CCFlag) of WR with the analysed parameter.
Results
Statistically, significant changes were also found for CCFmax(˙VO2musc) between L-236 and R+6 (P = 0.010), L-236 and R+21 (P = 0.030), L-72 and R+6 (P = 0.043). Between pre-to-post mission change in ˙VO2peak and CCFmax(HR), a correlation was shown (r SP = 0.67, P = 0.017).
Conclusion
The ˙VO2musc kinetics changes indicate aerobic detraining effects which are present up to 21 days following space flight. The correlations between changes in ˙VO2peak and HR kinetics illustrate the key role of cardiovascular regulation in ˙VO2peak. The addition of CRKT to ISS flight is recommended to obtain information regarding the potential muscular and cardiovascular deconditioning. This allows a reduction in the frequency of higher intensity testing during flight.
Heart rate (HR), pulmonary and muscle oxygen uptake (˙VO2pulm, ˙VO2musc) kinetics after changes of work rate (WR) indicate regulatory characteristics related to aerobic metabolism. We analysed whether the kinetics of HR, ˙VO2pulm and ˙VO2musc are slowed after missions to the International Space Station (ISS). The changes of the kinetics were correlated with ˙VO2peak data.
Methods
10 astronauts [4 females, 6 males, age: 48.0 ± 3.8 years, height: 176 ± 7 cm, mass: 74.5 ± 15.9 kg (mean ± SD)] performed an incremental test to determine ˙VO2peak (before missions on L-110 days, after return on R+1/+10/+36 days), and a cardio-respiratory kinetics test (CRKT) with randomized 30–80 W WR changes to determine HR, ˙VO2pulm and ˙VO2musc kinetics by time-series analysis (L-236/-73, R+6/+21). Kinetics were summarized by maximum and related lag of cross-correlation function (CCFmax, CCFlag) of WR with the analysed parameter.
Results
Statistically, significant changes were also found for CCFmax(˙VO2musc) between L-236 and R+6 (P = 0.010), L-236 and R+21 (P = 0.030), L-72 and R+6 (P = 0.043). Between pre-to-post mission change in ˙VO2peak and CCFmax(HR), a correlation was shown (r SP = 0.67, P = 0.017).
Conclusion
The ˙VO2musc kinetics changes indicate aerobic detraining effects which are present up to 21 days following space flight. The correlations between changes in ˙VO2peak and HR kinetics illustrate the key role of cardiovascular regulation in ˙VO2peak. The addition of CRKT to ISS flight is recommended to obtain information regarding the potential muscular and cardiovascular deconditioning. This allows a reduction in the frequency of higher intensity testing during flight.
| Originalsprache | Englisch |
|---|---|
| Zeitschrift | European journal of applied physiology |
| Jahrgang | 116 |
| Seiten (von - bis) | 503-511 |
| ISSN | 1439-6319 |
| Publikationsstatus | Veröffentlicht - 2015 |