Osteoporosis, a disease that afflicts bone structure, leaving them weakened and sometimes deformed, is a serious problem for many people, especially women who have undergone hormonal changes as part of the natural aging process. Researchers with the National Space Biomedical Research Institute and from other medical research facilities have long used the unique and particularly demanding environment of space to improve their knowledge of osteoporosis and to develop better ways of preventing and treating it. The reason astronauts are so useful as human “guinea pigs” is because of the serious gravitational differences between the surface of the Earth and the vast expanses beyond Earth’s atmosphere. The sense of weightlessness that accompanies space travel has been determined through the study of astronauts upon their return to Earth to have a deleterious effect on bone density, with longer periods in lower gravity environments presenting ever-greater challenges for maintaining bone strength. In other words, the longer one is orbiting the Earth, the more cognizant he or she must be of the diminishing effect weightlessness is having on his or her body, especially bone and muscle strength. This is why astronauts spending long periods of time in space must exercise on treadmills, to maintain muscle and bone strength.
Space travel speeds up the aging process because of the effects of greatly diminished gravitational forces on bone cells. Studying the effects of gravitational perturbations on astronauts is an invaluable method for better understanding osteoporosis and for developing ways to treat it.