An unusual experiment involving Canada took place at the Institut de médecine et de physiologie spatiales (MEDES) (available in French only) in Toulouse, France. Twenty-four women volunteers spent two months in bed lying with their heads slightly below horizontal (six degrees). Twelve took part in the experiment from March to May 2005, while the twelve others were at the clinic from September to November 2005.
The bedrest study was called WISE (Women International Space Simulation for Exploration). It was designed to study the effects of microgravity on the human body-without having to go into space.
The head-lower-than-feet bedrest position simulates the effects of weightlessness on the human body: the muscles atrophy due to a lack of physical activity, the heart rate increases, blood pressure rises, and there is a loss of coordination. WISE also studied the psychological effects of isolation, monotony, and low mobility—conditions similar to those faced by astronauts who spend long periods aboard the International Space Station.
Throughout the study, the candidates, who were recruited in Europe through a rigorous selection process, did all daily activities in bed. They remained in the prone position for meals, exercise and washing—even for entertainment! They used their free time to watch television, study a new language or a subject that interests them. There was just one condition: they had to stay in bed.
The candidates were divided into three groups and followed a strict research protocol to the letter to ensure conclusive results. Four women did physical exercise, with the help of physiotherapists; four ate a protein-rich diet; and four were the control group, for whom the research protocol did not include exercise or a special diet. All candidates underwent regular medical examinations and followed a controlled diet.
A complete medical team followed the volunteers. Several specialists are studying the effects of bedrest on the bones, heart, muscles, circulatory system, and brain. They are also observing its impact on the psychological well-being of the subjects.
Two of the WISE scientists are Canadian: Dr. Guy Trudel, of the University of Ottawa's Department of Medicine, and Dr. Richard Hughson, of the Department of Kinesiology at the University of Waterloo.
Dr. Trudel is studying reactions to long periods of inactivity, including the reduction in the number of blood-forming cells in bone marrow, and the increased risk of tendinitis and fat accumulation in the muscles. Dr. Hughson is looking mainly at changes in the cardiovascular system, in its structure and function. Their findings will be compared to what has been seen in astronauts who have completed space missions.
In addition to doctors, a medical and paramedical support team, including nurses and psychologists, was assigned to the clinic to support the volunteer subjects.
WISE is an opportunity to test methods that may offset the physiological and psychological effects of bedrest. In particular, they tested therapeutic physical exercises and a special diet. These could have similar beneficial effects for astronauts.
The WISE study creators chose to focus on female subjects because so little data exists on the adaptation of the female body to weightlessness and on how to reduce the effects of microgravity on women. In 2001, a similar study was done on male subjects which may be used for comparison. One thing is certain: bones are sensitive to microgravity and quickly lose density in a degenerative process similar to osteoporosis.
With more women astronauts participating in space missions and several space agencies planning long-term missions to other planets, an improved understanding of the effects of microgravity on the human body is essential.
At the conclusion of the experiment, the candidates, who are between 25 and 40 years old, were examined and took part in physiotherapy sessions to reacclimatize their bodies to normal equilibrium and walking.
The Canadian Space Agency helped finance the participation of Dr. Trudel and Dr. Richard Hughson in this international study, which was led by the European Space Agency with NASA and the
French Centre national d'études spatiales (CNES).