Health Benefits of Exercise in Space for Astronauts

Understanding Orthostatic Intolerance

A recent study has highlighted the health advantages of exercise in space, particularly in alleviating post-flight orthostatic intolerance among astronauts returning to Earth. Orthostatic hypotension refers to a drop in blood pressure that occurs when a person stands up after sitting or lying down. This condition can cause dizziness, lightheadedness, and even fainting. Orthostatic intolerance has emerged as a significant medical concern for astronauts after their return from space, primarily due to cardiovascular deconditioning.

Key Findings from the Study

Coinciding with the 50th anniversary of the Apollo 11 moon landing, a research team led by The University of Texas Southwestern Medical Center identified methods to help prevent astronauts from fainting upon returning to Earth. Funded by NASA, the findings were published in the American Heart Association’s journal, Circulation.

The study involved 12 astronauts who spent approximately six months in space, where they were required to engage in personalized endurance and resistance exercise training for up to two hours daily. Researchers meticulously monitored their blood pressure and heart rate continuously before, during, and after the six-month mission, with a saline infusion administered upon landing.

Impact of Exercise and IV Fluids

The research revealed that exercising for one hour or more each day was effective in preventing cardiovascular, bone, and muscle deconditioning. Additionally, when this exercise regimen was paired with intravenous (IV) fluids upon returning to Earth, instances of orthostatic hypotension were completely avoided.

Future Research Directions

This groundbreaking study enhances our understanding of low blood pressure issues faced by astronauts. The research team plans to conduct further studies involving a larger cohort of astronauts and those who spend extended periods in space to validate their findings.

Reference

Fu et al. Impact of Prolonged Spaceflight on Orthostatic Tolerance During Ambulation, and Blood Pressure Profiles in Astronauts. Circulation, 2019, Article in Press. DOI: 10.1161/CIRCULATIONAHA.119.041050.

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