Space Physiology and Technology: Adaptations, Countermeasures, and Opportunities for Wearable Systems.

Space poses substantial challenges for humans, leading to physiological adaptations in response to an environment vastly different from Earth. A comprehensive understanding of these physiological adaptations is necessary to develop effective countermeasures that support human life in space. This narrative review first focuses on the impact of the space environment on the musculoskeletal system. It highlights the complex interplay between bone and muscle adaptations and their implications on astronaut health. Despite advances in current countermeasures, such as resistive exercise and pharmacological interventions, they remain partially effective, bulky, and resource-intensive, posing challenges for future missions aboard compact spacecraft. This review proposes wearable sensing and robotic technologies as promising alternatives to overcome these limitations. Wearable systems, such as sensor-integrated suits and (soft) exoskeletons, can provide real-time monitoring, dynamic loading, and exercise protocols tailored to individual needs. These systems are lightweight, modular, and capable of operating in confined environments, making them ideal for long-duration missions. In addition to space applications, wearable technologies hold considerable promise for terrestrial uses. They could support rehabilitation and assistance for the aging population and individuals with musculoskeletal disorders, and enhance physical performance in healthy users. By integrating advanced materials, sensors, actuators, and intelligent, energy-efficient control, these technologies can bridge gaps in current countermeasures while enabling broader applications on Earth.