Observing astronauts to better understand the mechanisms of the human body on Earth: space travel offers a unique model of extreme physical inactivity. The pathologies in question include cardiovascular risks and osteoporosis, but also metabolic disorders like obesity and diabetes. At the next Mardi de l’espace (Space Tuesday), two experts, Stéphane Blanc of the CNRS and Guillemette Gauquelin-Koch of the CNES, will discuss the importance of space research on sedentary lifestyles—a more and more pressing subject.
Credit: NASA Spinoff
Would you be prepared to stay confined to your bed for over three months straight? If so, great: medical research regularly seeks candidates for this type of experiment. The goal is to observe the effects of physical inactivity or of weightlessness on the human body. But the ideal guinea pig for this kind of study is actually the astronaut. Weightlessness and confinement inflict on the body extreme conditions that resemble long-term lack of movement. In microgravity, the body no longer needs to “fight” against the gravitational pull of the Earth. Muscles and bones have less work to do. To counter the effects of lack of activity, astronauts do, on average, two hours of exercise per day.
“Physical inactivity will become a significant health issue. It’s become more and more crucial to understand better the consequences of inactivity for the metabolism, muscles and bones,” explains Guillemette Gauquelin-Koch, head of the Life Sciences programs at the CNES. Overweight individuals now represent more than a third of the global population. “People don’t do enough sport anymore. And, yet, it’s essential.” Without exercise, the body can develop serious pathologies. The worrying increase in cases of obesity and diabetes is a red flag.
Experiments in space have the advantage of offering an environment that recreates, in little time, what long-term lack of movement can do to the human body. Space provides a very interesting, but also very restrictive, context for observations. “The technical and administrative constraints are significant. Only one or two astronauts per year participate in this kind of program. From the time when the experiment is proposed to the moment when the results are obtained, between five and ten years can go by,” explains Stéphane Blanc, Deputy Scientific Director of the Institute for Ecology and Environment of the CNRS, and a specialist of muscles, metabolism and nutrition under extreme conditions.
The two experts who will join us for this Space Tuesday regularly have the opportunity to work together. In 2013, they participated in the Mice Telemetry on Bion (MTB) project. The CNES, in cooperation with the Institute of Biomedical Problems (IMBP) of Moscow, sent a crew of 15 mice to spend a month aboard a biosatellite. “Muscle biopsies, in particular, were carried out. These are still rarely authorized on astronauts,” Stéphane Blanc explains.
How does the human body react to extreme physical inactivity? What dangers does this present for health? What possibilities exist for upcoming experiments in weightlessness, and what discoveries might be made, now or in the future? To address these questions, the CNES, MyScienceWork and the Bar des sciences invite you to participate in the next Mardi de l’espace, tonight, 21 January, at 7:30 at the Café du Pont Neuf in Paris. Or join us online on Twitter, via the hashtag #CNESTweetup.