An exercise protocol designed to control energy expenditure for long-term space missions

Area of Science:

• Exercise Physiology
• Space Medicine
• Metabolic Studies

Background:

• Astronauts face significant weight loss during spaceflight.
• Maintaining work efficiency and managing energy expenditure (EE) are critical for future space missions.
• Excess post-exercise energy expenditure (EPEE) is a key factor in total EE during exercise protocols.

Purpose of the Study:

• To compare the total energy expenditure (EE), including excess post-exercise energy expenditure (EPEE), of two interval cycling protocols against continuous aerobic training.
• To identify optimal exercise strategies for energy management in spaceflight.

Main Methods:

• 10 healthy men completed three cycling sessions: sprint interval training (SIT), high-intensity interval aerobic training (HIAT), and continuous aerobic training (CAT).
• Measurements included resting metabolic rate, exercise EE, and 180-minute post-exercise EE for each protocol.
• SIT involved 7x30s at 120% VO2max with 15s rest; HIAT involved 3x3min at 80-90% VO2max with 2min active rest; CAT involved 40min at 60-65% VO2max.

Main Results:

• Total EE averaged 109 kcal for SIT, 182 kcal for HIAT, and 363 kcal for CAT.
• EPEE averaged 32 kcal for SIT, 21 kcal for HIAT, and 13 kcal for CAT.
• Continuous aerobic training resulted in the highest total EE, while SIT had the highest EPEE.

Conclusions:

• Sprint interval training (SIT) and high-intensity interval aerobic training (HIAT) are potential protocols for controlling energy expenditure during long space missions.
• These interval training methods may offer a more efficient approach to energy management compared to continuous training for astronauts.