Deep space exploration: Sleep and circadian rhythms in heart and brain function

Area of Science:

• Space medicine
• Neuroscience
• Cardiology

Background:

• Astronauts experience unique stressors like microgravity, radiation, and circadian rhythm disruption.
• These stressors can lead to physiological changes, particularly affecting the heart and brain.

Purpose of the Study:

• To review alterations in heart and brain function during spaceflight.
• To explore the links between these changes and environmental/physiological stressors.
• To inform strategies for lunar and Mars missions.

Main Methods:

• Review of spaceflight observations and experiments.
• Analysis of ground-based analog and mechanistic studies.
• Examination of evidence for mitochondrial dysfunction, oxidative stress, and inflammation.

Main Results:

• Spaceflight is associated with functional alterations in the heart and brain.
• Potential mechanisms include mitochondrial dysfunction, oxidative stress, and autonomic dysregulation.
• Direct causal evidence in astronauts is limited and requires further validation.

Conclusions:

• Circadian rhythm dysregulation and sleep disturbance may significantly impact astronaut cardiovascular and neurological health.
• Understanding these links is crucial for developing effective monitoring and countermeasures.
• Further research under actual spaceflight conditions is needed to validate findings.