Cardiovascular effects of microgravity: evolution of understanding

The understanding of cardiovascular effects of spaceflight has evolved throughout the course of the American manned spaceflight program. Originally descriptive in nature, the present understanding is based on empiric measurements of vascular volume, cardiac output, vascular reflexes, and peripheral and central autonomic control. More detailed understanding of cardiovascular effects has allowed us to separate those symptoms from symptoms caused by musculoskeletal or neurovestibular abnormalities.