Exercise Could Help Women On Bed Rest

Short but intense sessions of exercise may help women on bed rest stay strong and recuperate more quickly, according to a NASA-funded study by researchers at Ball State University, Muncie, Ind. The findings of the first comprehensive bed rest study focusing exclusively on women will help NASA develop more effective countermeasures to mitigate strength and muscle loss in female astronauts on long-duration missions to the International Space Station and, perhaps, someday to Mars.

It also may have implications for women on Earth confined to bed rest because of illness, injury or pregnancy.

"With NASA astronaut Peggy Whitson commanding the International Space Station now and astronaut Pam Melroy commanding the last space shuttle mission, we're reminded daily that women make up an important segment of our astronaut corps and are taking on more and more leadership roles," said Carl Walz, a former long-duration astronaut and head of NASA's advanced capabilities division in the agency's Exploration Systems Mission Directorate, Washington. "It's important that we look at how space travel -- microgravity, radiation, and other factors -- affects women and men differently."

Ball State's Human Performance Lab has been working with NASA for more than a decade to examine the impact spaceflight has on humans, according to Scott Trappe, the lab's director. He co-authored the study with fellow lab researcher Todd Trappe, his brother.

"Until we completed this study, we had no solid research on how women would adapt to long durations in space," Trappe said. "This information should have a dramatic impact for NASA in the coming years."

Conducted in Toulouse, France, the study was sponsored jointly by the European Space Agency, the Canadian Space Agency, the French space agency CNES, and NASA. Results were published recently in the Journal of Applied Physiology and Acta Physiologica.

The study examined 24 female participants to determine whether specific exercise regimens or nutritional supplements could prevent the loss of lower body muscle mass and strength.

The women spent 60 days on bed rest. They lay with their heads pointing downward at a 6-degree angle, which researchers believe most accurately simulates the weightless conditions of space. One group was put on an exercise regimen. A second group was put on a high-protein diet rich with leucine, an amino acid. The control group did not take part in any exercise or dietary protocols.

"When we looked at these women after two months, the difference in the physical condition among the three groups was undeniable," Trappe said. "The women who did not exercise lost nearly half their strength in some cases. What's more, the group who ate a high-protein diet but did not exercise lost even more muscle mass than the control group."

The exercise regimen included a 40 to 50 minute aerobic workout two or three times a week and 20-minute strength training sessions two or three