CARDIODYNAMIC AND METABOLIC EFFECTS OF PROLONGED BED REST.
Final rept. Apr 62-Apr 63,
LANKENAU HOSPITAL RESEARCH INST PHILADELPHIA PA
Pagination or Media Count:
To evaluate the circulatory and metabolic effects of prolonged inactivity, urinary nitrogen, cal cium, and phosphorus excretion were measured in four healthy trained men on a constant diet 2500 Cal., 77 gm protein, 74 gm fat, 385 gm CHO, 1724 mg calcium during 42 days of continuous supine bed rest. Maximum oxygen uptake and hemodynamic response to 70 degree head-up tilt and supine bicycle exercise at 3 and 6 times resting oxygen uptake levels were determined pre-and post-bed rest. Urinary excretion of calcium and phosphorus increased within the first six days. Calcium excretion reached a peak approximately twice con trol values after 24 days. No significant change occurred in urinary nitrogen. Tolerance to 70 degree head-up tilt and physical work capacity decreased following bed rest, but a satisfactory cardiodynamic response to supine exercise was maintained. Physical work capacity returned to near pre-bed rest values after 18 days of retrain ing. Author