Acceleration with exercise during head-down bed rest preserves upright exercise responses.

Keisho Katayama; Kohei Sato; Hiroshi Akima; Koji Ishida; Hiroki Takada; Yoriko Watanabe; Mitsunori Iwase; Miharu Miyamura; Satoshi Iwase

PubMed · 15619856

Acceleration with exercise during head-down bed rest preserves upright exercise responses.

Keisho Katayama·Kohei Sato·Hiroshi Akima·Koji Ishida·Hiroki Takada·Yoriko Watanabe·Mitsunori Iwase·Miharu Miyamura·Satoshi Iwase

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Abstract

INTRODUCTION: This study was designed to elucidate the effect of short-arm centrifuge-induced artificial gravity with exercise training during ground-based simulated spaceflight, i.e., prolonged head-down bed rest (HDBR), on respiratory and cardiovascular responses to upright exercise. METHODS: There were 10 healthy men who underwent 20 d of -6 degrees HDBR, and were assigned to either a countermeasure (CM) group (n = 5) or a no countermeasure (No-CM) group (n = 5). The subjects in the CM group performed two sessions (20 min each session, 40 min total) of short-arm centrifuge-induced artificial gravity with exercise training in a supine position on alternate days (10 d total) during HDBR. The first session was set at 0.8-1.4 G load at heart level with a constant exercise intensity (60 W), and the second session began with a 0.3 G load at heart level with an interval exercise protocol (40-80% peak oxygen uptake; VO2peak). The measurements of respiratory and cardiovascular responses to incremental exercise were performed pre- and post-HDBR. RESULTS: The 20 d of HDBR increased minute expired ventilation, heart rate, and respiratory exchange ratio and decreased stroke volume during submaximal exercise in the No-CM group, whereas these parameters were unchanged in the CM group. In the No-CM group, VO2peak decreased significantly (47.0 +/- 8.6 to 34.8 +/- 6.8 ml x kg(-1) x min(-1), p < 0.05), whereas VO2peak in the CM group did not show a significant decrease following 20 d of HDBR (47.7 +/- 10.0 to 43.9 +/- 8.9 ml x kg(-1) x min(-1)). These results suggest that short-arm centrifuge-induced artificial gravity with exercise training is effective in maintaining respiratory and cardiovascular responses to upright exercise.

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Adolescent Adult Centrifugation Exercise Heart Rate Humans Hypogravity Male Oxygen Consumption Physical Endurance Posture Space Flight Journal Article Research Support, Non-U.S. Gov't

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Keisho Katayama, Kohei Sato, Hiroshi Akima, Koji Ishida, Hiroki Takada, Yoriko Watanabe, Mitsunori Iwase, Miharu Miyamura, Satoshi Iwase. 2004. Acceleration with exercise during head-down bed rest preserves upright exercise responses.. https://pubmed.ncbi.nlm.nih.gov/15619856/

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