Immersive gamma music as a tool for enhancing glymphatic clearance in astronauts while improving their mental well-being.

Spaceflight occurs under extreme environmental conditions that pose significant risks to the physical and mental health and well-being of astronauts. Certain factors, such as prolonged isolation, monotony, disrupted circadian rhythms, heavy workload, and weightlessness in space, can trigger psychological distress and may contribute to a variety of mental health problems, including mood and anxiety disturbances. Recent findings regarding spaceflight-associated alterations in cerebrospinal fluid spaces, demonstrating enlargement of the brain's perivascular spaces from preflight to postflight, at least suggest reduced glymphatic clearance in microgravity, and have raised concerns about long-term cognitive health in astronauts. Therefore, it is critical for future long-duration human exploration missions to identify, develop and validate all potentially effective long-term countermeasures capable of reducing the risk of perivascular space enlargement and impaired glymphatic transport in space mission crews. Furthermore, it is crucial to implement effective strategies that would allow crew members to maintain optimal psychological well-being during future long-duration space exploration. In the present paper, we propose "immersive gamma music" as an add-on countermeasure that in combination with existing countermeasures can optimize glymphatic clearance in astronauts while improving their mental well-being. If confirmed, this approach could enrich the practice of space medicine, and might become increasingly important, given the plans for future human missions, including a return to the Moon and manned missions to Mars.