NASA astronaut Sandy Magnus works out on the Advanced Resistive Exercise Device aboard the International Space Station. Image Credit: NASA
A new study of 13 International Space Station astronauts suggests a combination of strenuous weightlifting-like exercise and careful attention to diet and nutrition can stave off the bone loss long thought by experts to be an obstacle to long missions by astronauts to deep space destinations.
The study of nine men and four women assigned to the orbiting science laboratory between 2006 and 2009 was focused on the addition of the Advanced Resistive Exercise Device in late 2008.
The ARED joined a treadmill, bicycle ergometer and the less physically taxing Interim Resistive Exercise Device as the primary workout equipment used by station astronauts for more than two hours each day to maintain muscle and bone strength in the absence of gravity.
The ARED doubled the resistive force of the IRAD -- up to 600 pounds -- available to astronauts and increased from eight to 17 the kinds of weightlifting exercises they can perform, including squats, dead lifts, bench presses and curls.
The study compared results from pre and post-flight measurements of bone mineral density and bone mineral content in the eight astronauts who used the IRAD and five who used the ARED as part of their assigned daily exercise regimes. ARED use demonstrated a marked improvement, most noticeable in the pelvic, hip and lumbar spine regions of the skeletal system.
"After 51 years of human spaceflight, these data mark the first significant progress in protecting bone through diet and exercise," said Scott M. Smith, NASA nutritionist at the agency's Johnson Space Center in Houston and lead author of the 11-page study published in the September edition of the Journal of Bone and Mineral Research.
Prior to the ISS, medical specialists focused their efforts primarily on the use of aerobic exercise using treadmills, cycle ergometers and elastic expanders to mitigate bone and muscle loss.
Smith and a team that included five other researchers from the U.S. and Germany also found that daily diet and vitamin D supplements were an essential part of facilitating the normal rebuilding of bone strength, also called remodeling.
The research team urged further work in several key areas, including refinements in the optical exercise protocols and nutritional requirements as well as assessments of whether the remodeled bone is as strong as pre-flight skeletal tissue.
The study results were gathered using X-ray densitometry, blood and urine samples and a dietary log recorded by the astronauts.