| Autor: |
Hedge ET; Schlegel-UW Research Institute for Aging, Waterloo, Ontario, Canada.; Department of Kinesiology and Health Sciences, University of Waterloo, Waterloo, Ontario, Canada., Mastrandrea CJ; Schlegel-UW Research Institute for Aging, Waterloo, Ontario, Canada., Hughson RL; Schlegel-UW Research Institute for Aging, Waterloo, Ontario, Canada. |
| Jazyk: |
angličtina |
| Zdroj: |
Journal of applied physiology (Bethesda, Md. : 1985) [J Appl Physiol (1985)] 2023 Apr 01; Vol. 134 (4), pp. 1022-1031. Date of Electronic Publication: 2023 Mar 17. |
| DOI: |
10.1152/japplphysiol.00726.2022 |
| Abstrakt: |
Cardiorespiratory fitness declines with age and this decline can be accelerated by inactivity and bed rest. Recovery of fitness is possible, but the timeline in 55- to 65-yr-old adults is unknown. Furthermore, the effectiveness of exercise to prevent deconditioning during bed rest is unexplored in this age group. Twenty-two adults (11 women, 59 ± 3 yr) completed 2 wk of strict 6° head-down bed rest (HDBR). Half of the participants performed approximately 1 h of daily exercises, including high-intensity interval cycling, aerobic cycling, and upper- and lower-body resistance training, whereas control participants were inactive. Step-incremental cycling tests to exhaustion were conducted pre-HDBR and at three times during the recovery phase ( day 1 or 2 , day 6 , and 4 wk) to assess peak oxygen uptake (V̇o 2 ). Peak V̇o 2 was reduced in the control group throughout the first 6 days of recovery, but did return to pre-HDBR levels by the 4-wk recovery time point (interaction: P = 0.002). In the exercise group, peak V̇o 2 was not different at any time point during recovery from pre-HDBR. Ventilatory threshold V̇o 2 (interaction: P = 0.002) and heart rate at 15 W (interaction: P = 0.055) mirrored the changes in peak V̇o 2 in each respective group. Overall, this study showed that approximately 1 h of daily exercise effectively protected 55- to 65-yr-old adults' cardiorespiratory fitness during 2 wk of HDBR. HDBR without exercise countermeasures caused substantial reductions in cardiorespiratory fitness, but fitness recovered within 4 wk of resuming daily activities. These findings highlight the importance of physical activity in late middle-age adults. NEW & NOTEWORTHY We report the complete time-course of cardiorespiratory fitness recovery back to baseline levels following 2 wk of head-down bed rest in 55- to 65-yr-old adults and found that multimodal training, consisting of high-intensity interval, aerobic and resistive exercises, performed throughout the 2 wk of head-down bed rest prevented reductions in cardiorespiratory fitness. |
| Databáze: |
MEDLINE |
| Externí odkaz: |
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