Modification of orthostatic tolerance with periodic lower body negative pressure

Returning astronauts have repeatedly displayed reduced orthostatic tolerance. Ground-based simulations of the weightless state such as water immersion and bedrest can reliably produce similar orthostatic intolerance. Using LBNP to measure orthostatic tolerance, evidence is presented demonstrating that brief, repeated exposure to LBNP is readily capable of restoring the loss of orthostatic tolerance resulting from bedrest and water immersion. In stimulating natural orthostatic mechanisms, periodic LBNP may represent a practical and efficacious method of managing orthostatic intolerance aloft without the use of artificial gravity.