Metabolic and cardiovascular responses during sub-maximal exercise in humans after 14 days of head-down tilt bed rest and inactivity.
VO(2), f (H), Q, SV, [Hb], C(a)O(2), QaO(2), MAP and R (P) were measured in 10 young subjects at rest and during exercise at 50, 100 and 150 W before and after 14 days of head-down tilt bed rest (HDTBR) and of ambulatory (AMB) control period. f (H) was 18 and 8% higher after HDTBR and AMB, respectively. SV dropped by 15% both after HDTBR and AMB, whereas Q did not change. After HDTBR, C(a)O(2) decreased at rest (-8%) and at 50 W (-5%), whereas QaO(2) did not change; MAP was 14 and 6% lower at rest and at 100 W and R (P) decreased by 23% only at rest. Changes in f (H) and SV were larger after HDTBR than after AMB. These results show that, notwithstanding the drop of SV, moderate-intensity dynamic exercise elicited a normal pressure response after 14 days of HDTBR.
Capelli
C
C
School of Exercise and Sport Sciences, University of Verona, Via Felice Casorati, 43, 37131 Verona, Italy. carlo.capelli@univr.it
Antonutto
G
G
Cautero
M
M
Tam
E
E
Ferretti
G
G
D000328:Adult; D001510:Bed Rest / Q000009:adverse effects*; D001794:Blood Pressure; D002302:Cardiac Output; D018493:Cardiovascular Deconditioning; D015444:Exercise; D018475:Head-Down Tilt / Q000009:adverse effects*; D006339:Heart Rate; D006439:Hemodynamics; D006454:Hemoglobins / Q000378:metabolism; D006801:Humans; D008297:Male; D009119:Muscle Contraction; D018482:Muscle, Skeletal / Q000098:blood supply / Q000378:metabolism*; D010100:Oxygen / Q000097:blood; D010101:Oxygen Consumption; D013318:Stroke Volume; D013997:Time Factors; D018474:Weightlessness Simulation / Q000009:adverse effects*; D055815:Young Adult
D006454:Hemoglobins; D010100:Oxygen