For the Truly Discerning Traveler: A 10-day Jaunt in Space
Jeffrey Borer, MD, of Weill Cornell Medical College in New York, has been a senior biomedical advisor to NASA and chair of the NASA subcommittee at the National Institutes of Health since 1984. He tells WebMD that the space traveler encounters two very different types of problems. First is the immediate gravitational force felt during lift-off and the second is the "micro-gravity environment that exists in space."
Halvorson says most people think of this as zero gravity and can easily recall images of both astronauts and objects floating in the cabin of a space shuttle. The technical term, says Borer, is micro-gravity and it is not as friendly an environment as it may seem.
Micro-gravity affects the body in several ways, says Borer. "First there are muscular changes that can cause atrophy of skeletal muscles," he says. Halvorson says that "everyone gets bird legs, you know, skinny legs." Because the legs don't have to deal with the force of gravity, they have no work to do, says Borer. No work means that muscles can waste away. "The countermeasure to this is intensive exercise during part of every day," says Borer.
At the same time, micro-gravity causes bones to lose calcium and become fragile, says Borer. The bones lose so much calcium that the amount of calcium circulating in the blood increases, he says. Unfortunately some of this calcium finds its way to the kidneys where it can form kidney stones. "There is an increased risk for kidney stones with extended time in space," says Borer.
Probably the most unpleasant aspect of space travel for the space tourist would be space sickness, a type of nausea that is very similar to other types of motion sickness, says Borer. He says that this usually passes in a day or two.
Considering these problems, space travel is definitely no Love Boat cruise, but Borer says that extended space travel may pose even greater risks. For example, he says there are some indications that extended time in space may have an effect on each of the major organ systems. In the case of the heart -- Borer is a heart specialist -- some researchers think there could be some structural changes if one lived for years in a micro-gravity environment.