Engineering topics

Haskell, W. L.

Publications and source records attributed to Haskell, W. L..

3 records

NASA NTRS1990

Hemodynamic and ADH responses to central blood volume shifts in cardiac-denervated humans

Hemodynamic responses and antidiuretic hormone (ADH) were measured during body position changes designed to induce blood volume shifts in ten cardiac transplant recipients to assess the contribution of cardiac and vascular volume receptors in the control of ADH secretion. Each subject underwent 15 min of a control period in the seated posture, then assumed a lying posture for 30 min at 6 deg head down tilt (HDT) followed by 20 min of seated recovery. Venous blood samples and cardiac dimensions (echocardiography) were taken at 0 and 15 min before HDT, 5, 15, and 30 min of HDT, and 5, 15, and 30 min of seated recovery. Blood samples were analyzed for hematocrit, plasma osmolality, plasma renin activity (PRA), and ADH. Resting plasma volume (PV) was measured by Evans blue dye and percent changes in PV during posture changes were calculated from changes in hematocrit. Heart rate (HR) and blood pressure (BP) were recorded every 2 min. Results indicate that cardiac volume receptors are not the only mechanism for the control of ADH release during acute blood volume shifts in man.

Convertino, V. A.↗

NASA NTRS1989

Exercise-training protocols for astronauts in microgravity

Based on physical working requirements for astronauts during intra- and extravehicular activity and on the findings from bed-rest studies that utilized exercise training as a countermeasure for the reduction of aerobic power, deterioration of muscular strength and endurance, decrements in mood and cognitive performance, and possibly for bone loss, two exercise protocols are proposed. One assumes that, during microgravity, astronaut exercise physiological functions should be maintained at 100 percent of ground-based levels. The other assumes that maximal aerobic power in flight can be reduced by 10 percent of the ground-based level.

Greenleaf, J. E.↗

NASA NTRS1972

The National Aeronautics and Space Administration-U.S. Public Health Service Health Evaluation and Enhancement Program - Summary of results.

An exercise program was initiated in a federal agency to assess the feasibility of such a program, and to identify the factors that influenced joining, adherence to, and effectiveness of the program. The program was utilized by 237 of the 998 eligible federal employees; mean attendance rate was 1.3 days/week. Those who volunteered perceived a need for increased physical activity, believed they had sufficient time to participate and derived subjective as well as objective benefits. Significant improvements were found in heart rate response to the standard exercise test, body weight, skinfold measurements and triglyceride levels.

Durbeck, D. C.↗