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High intensity training during spaceflight: results from the NASA Sprint Study
Kirk L English1,2, Meghan Downs3, Elizabeth Goetchius4
1University of Houston-Clear Lake, Houston, TX USA.
NPJ Microgravity
|September 1, 2020
Summary
New high-intensity, lower-volume exercise programs for astronauts on the International Space Station (ISS) show promise. This training may help maintain fitness while reducing exercise time, crucial for long-duration spaceflight missions.
Area of Science:
- Space Medicine
- Exercise Physiology
- Astronaut Health
Background:
- International Space Station (ISS) exercise countermeasures have historically failed to fully preserve astronaut musculoskeletal and cardiorespiratory fitness during long-duration spaceflight.
- While recent missions have seen reduced losses, optimizing exercise protocols is key to freeing up astronaut time for other critical tasks.
Purpose of the Study:
- To evaluate the effectiveness of a novel, integrated high-intensity/lower-volume exercise prescription compared to the standard ISS countermeasure.
- To determine if the new program can maintain astronaut physical fitness with reduced time commitment.
Main Methods:
- ISS crewmembers were assigned to either a Sprint (high-intensity/lower-volume) program or the standard ISS countermeasure program.
- Key physiological measures including bone mineral density (DXA), muscle strength (isokinetic dynamometry), muscle function (cone agility test), and cardiorespiratory fitness (VO2peak) were assessed pre- and post-flight.
- Mixed-effects modeling was used for data analysis with a significance level of P < 0.05.
Main Results:
- Both groups experienced decreases in femoral neck bone mineral density, knee extensor peak torque, cone agility test performance, and VO2peak post-spaceflight.
- The Sprint group demonstrated attenuated or no loss in these parameters compared to the control group in several instances.
- No significant physiological differences were observed between the two exercise programs overall.
Conclusions:
- While overall physiological outcomes were similar, the high-intensity/lower-volume Sprint program offers a time-efficient alternative for maintaining astronaut fitness.
- This training approach should be considered an essential component of spaceflight exercise countermeasures to better prepare astronauts for physically demanding mission tasks.
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