Effects of daily mild supine exercise on physical performance after 20 days bed rest in young persons

To investigate the effects of daily mild supine exercise on physical performance capacity identified as maximal oxygen uptake rate (VO2max) after 20 days bedrest, 3 male students performed a supine pedaling at 40% intensity of VO2max for one hour every day, while 6 male and 5 female students were control. Before and after the bedrest, muscle mass and strength of exercising leg and cardiovascular responses during -40mmHg lower body negative pressure (LBNP) and moderate upright cycling exercise were measured. Despite the exercise programme VO2max was similarly decreased to the control subjects after bed-rest. The delta VO2max was correlated to delta % left ventricular fractional shortening during LBNP, and also % delta VO2max to % delta stroke volume of the moderate exercise (both p<0.05). The exercise programme should be too weak to maintain cardiovascular functions and thus to present the decrease in VO2max against prolonged bedrest as well as weightlessness stress.