Pumping Iron Could Be Key to Maintaining Fit Astronauts
When America’s first space station orbits Earth in the early 1990s, at least one compartment aboard the module 200 miles out in the cosmos will look like an earthbound exercise studio.
Studies under way at the University of California, Irvine, show that short and prolonged missions in space cause rapid loss of proteins that help keep muscles in shape on Earth.
“In zero gravity we have to add a sufficient degree of stress on the muscle to counteract the natural tendency toward atrophy in space,” Dr. Kenneth Baldwin of the College of Medicine said.
The research shows that gravity dictates the action of two key muscle fiber proteins, and in the absence of the force that keeps things firmly in place on Earth, muscle tissue rapidly degenerates.
Baldwin explained that space missions as short as seven days have caused such detectable levels of muscle atrophy that it is apparent astronauts are not being properly trained.
No Mechanical Stress From Aerobics
“Over the last few years, we’ve been programmed into the notion that aerobic activities--jogging, cycling, running--are good, but they are not designed to add mechanical stress to the musculoskeletal system,” he said.
“What we need is a device that essentially provides a form of hydraulic stress so that you can push against a system that will put mechanical pressure on the muscles” to build strength before and during space voyages, Baldwin said.
NASA is listening.
Dr. William K. Douglas, who served as physician to the Mercury astronauts and now is on the McDonnell-Douglas research team designing a health maintenance compartment in the space station, said some good ideas are on the drawing board.
“Several have been suggested, like the Nordic track, which simulates cross-country skiing, complete with poles and skis.
“There’s also another that simulates climbing a mountain. The astronaut would have to climb against tension and exercise the whole body,” he said.
Baldwin, an exercise physiologist, is focusing his research on myosin proteins, which are produced by muscle cells.
Essential Components of Contraction
“Myosin is one of the essential components of the contraction response and we have found that different kinds of myosin figure in certain contractile activities,” he said.
Muscle tissues of humans and almost all other animals consist of two types of myosin--fast myosin for “fast-twitch” muscle fibers, which contract rapidly, and slow myosin for “slow-twitch” fibers, which contract more slowly.
It is slow myosin that evolved in man as the protein that helps muscles fight gravity and maintain an upright posture.
The physiologist believes that astronauts do not retain enough slow myosin during space missions because there is no need for a protein that acts against gravitational forces.
Baldwin and his team are trying to design exercises that will help astronauts produce more slow myosin. He said the body-building regimens might also fight bone degeneration, another problem detected in zero gravity.