We think of gravity as the force that makes apples fall off trees and allows skiers enjoy the thrill of sliding downhill. When it come to ourselves though, we tend to view gravity as the enemy that drags us down and ages us. It makes our body sag, muscles and bones atrophy, we lose our balance and coordination and cannot get a good night's sleep. Did you know that astronauts in space, where they experience almost no gravity-- we call it microgravity -- show the same changes? Do astronauts grow old faster in space without gravity? And if these changes are due to aging, why do they recover once back in Earth's gravity? After all, we presume that you and I grounded here on Earth do not recover from these same changes.These were the perplexing questions I faced in my research at NASA.
Developing a Ground Model
Given the small numbers of humans going into space, experiments on the ground had to be devised where we could study in depth many more people in conditions that mimic the effects of living in space. Healthy men and women, similar in age to astronauts, volunteered to lie in bed continuously for weeks. Lying down decreases the length of the axis in the body through which gravity can act. An even better model was lying at an incline with the feet up and head slightly down. The first 20 minutes are a bit uncomfortable because the blood rushes to the head but after that it feels normal and astronauts tell us it feels much more like being in space.
After a few days of this bed rest, healthy young volunteers show the same accelerated age-like loss in muscle and bone and the other spaceflight changes we saw in astronauts, except they were less intense. Were these healthy men and women also aging faster merely by lying in bed? Like astronauts, they also recovered once they were up and about and the axis of gravity acted on their body in the head to toe direction.
Answers Came from the Ground
The simplistic answer was that these changes may seem similar but are due to different causes and mechanisms. After all it has been assumed that as we age we do not recover from these similar changes.
While visiting a friend's mother at a nursing home it dawned on me that the question I was asking should be turned around. It was not, " Do astronauts and people on earth grow old under conditions of reduced gravity?" Outrageous as it seemed, what if the question to ask was "Could the physical deterioration associated with the passage of time be reversible as well?" " My research team wondered if it could have something to do with somehow being exposed to less gravity as we age. This consideration raised a highly exciting prospect.
The Theory and the Action
Years after first expressing this theory acceptance is gradually growing that the changes associated with increasing years -- age -- are distinct from aging. They are ageless. They are due to a life of reduced influence of gravity on the body. This means that they are not inevitable, that you can actually do something to prevent, delay and even reverse the changes normally associated with aging. Even though gravity is all around us, from age 20 on when development peaks, we progressively decrease challenging gravity in everyday life. It is not merely about inactivity. Not only do you sit more but the secret from space research is that you need to move more with respect to the axis of gravity.Think about gravity until using it becomes a habit.