Eat, Move, Think by Shaun Francis

Author:Shaun Francis
Language: eng
Format: epub
Publisher: Simon & Schuster

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WHAT’S THE BEST WAY TO MAINTAIN STRONG BONES?

Anything that bashes and puts an accelerative force on the bones will help keep them strong. One person who knows about the practical side of bone strength and weakness is Timothy Kopra, a US Army colonel and astronaut who has spent 244 days in space over two missions and served as the commander of the International Space Station.

The rough rule of thumb for astronauts is that without exercise they lose about 2 percent of their bone strength for each month that they’re in space. Exercise is intended to mitigate the effects of weightlessness; however, one survey of thirteen astronauts found that even if they did exercise, their bone strength decreased by an average of 14 percent during their six-month missions on the ISS. That decrease in bone strength then puts them at greater risk of breaking their hips later in life, when they’re back on Earth.

Astronauts on the space station have three basic options for exercise in the zero-gravity conditions of orbit. The most important one for protecting their bones is a weight machine known as the Advanced Resistive Exercise Device (ARED), which is designed to allow space station personnel to do any number of different resistance-based exercises. The ARED is equipped with springs and other motion dampeners to ensure that the inertial effects of weight lifting don’t damage the space station. Thankfully that’s not a concern on Earth, where it’s just as important for us terrestrial civilians to exercise regularly to maintain bone strength.

Osteoporosis, a disease in which the bones grow brittle and more susceptible to breaking, is something that was historically associated with women. But bone strength can be an issue in men, too. One in three women will get osteoporosis, and the condition will affect one in five men. More than 80 percent of fractures that happen after the age of 50 are the result of osteoporosis.

According to Osteoporosis Canada, peak bone mass exists between the ages of 16 and 20 in women and 20 to 25 in men. Even young adult and middle-aged men lose a little bone mineral density each year—somewhere between 0.4 and 1.5 percent annually. One estimate says that if men were tested for bone mineral density, a third of those over 65 would be prescribed calcium and vitamin D supplements, to build bone strength.

But supplement-based therapies have their problems. Side effects exist, and then there’s the cost. Exercise-based therapies may be more practical. They’re certainly cheaper. But what sort of exercise is best?

Any physical movement that stresses the bones will strengthen them. It’s a mechanism that comes from evolution—an action creates a stress on the body, and the body responds by changing itself to prepare for the next instance of the stress. In the case of a jarring or compressive force on the skeleton, the body interprets the force as a signal that it needs stronger bones to decrease the risk of injury the next time around, so it activates biological processes that make bones stronger.

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