Current approaches to mitigate the effect of microgravity on astronauts’ nutrition, physical activity and sleep: a narrative review

Introduction: The microgravity exerts enormous changes andimpact on human physiology, specifically on astronauts, such as their food habits, physical activity and awake-sleep cycle. Prolonged exposure to microgravity environments induces a series of adaptations and physiological changes that directly affect body composition, nutrient absorption, and sleep homeostasis. While essential for survival during spacial missions, these changes present significant challenges to the health and well-being of crew members, speciallay in long term missions. Objectives: To analyze the main effects of microgravity on astronauts regarding their food habits, physical activity, and sleep, and review the contemporary strategies to address them Methodology: To conduct this narrative review, scientific articles were searched in PubMed and ScieloPortugal, using the following keywords: “astronaut”, “microgravity”,“food intake”, “nutrition”, "physical activity”, “sleep”, combined with the Boolean operators AND or OR. Fifty three scientific publications were selected and analysed. Results: Literature studies showed that during, long-duration space flights, astronauts typically consume less energy than needed and present low energy availability, which can negatively affect their health with consequences upon body composition, including muscle and bone mass losses. In addition, sleep is also disrupted leading to physical and mental fatigue. Conclusion: Improved nutritional strategies and sleep hygiene are needed to ensure maintainance of an adequate energy availability during prolonged space missions.