After just a few days in space, reduced gravity begins to impact muscle density and function. During shuttle missions that last less than two weeks, it was noted that crewmembers often experience a reduction of their muscle fiber mass.
HRP studies have suggested that long-term stays in space could result in up to a 40% reduction in overall muscular function. Without intervention, this level of muscular function loss could increase crewmembers' risk of injury and impede their ability to perform mission-related tasks such as operating the spacecraft and other equipment. This is a challenge that HRP researchers and engineers must work to overcome for current and future space exploration.
Research is being done to help crewmembers maintain optimal muscle mass and function, and to ensure that they remain healthy and productive in the space environment and once back on Earth. Past research has shown that adherence to special exercise regimens before, during, and after spaceflight helps reduce the impact of gravity-related muscular changes. Current and future HRP research will strive to improve the types of exercises and equipment the crew use for protecting their muscle mass, strength, and endurance and to minimize the impact of reduced gravity environments and long-duration space travel on the human musculoskeletal system.