Animal study shows exercise when young prevents osteoporosis later on

Reported by Susan Aldridge, PhD, medical journalist

Kids who are physically active may gain lifelong bone strength that can protect against osteoporosis.
It is well known that exercise increases bone size and strength. The skeleton is most responsive to these benefits when young, so it may be that exercise in early life increases bone strength later on and so protects against osteoporosis. Researchers at Indiana University-Purdue University Indianapolis have carried out a study in rats to examine this theory.

They exercised the right forearms of five week old female rats for a few minutes three times a week for five weeks. They did not exercise the left forearms, for comparison. Bone quantity and structure of the forearms was measured before and after exercise. The researchers did not exercise the animals for the next 92 weeks, which was virtually the whole of their lifespan. At that point, the forearm bones were assessed again.

The results revealed that the strength gained from the exercise persisted throughout the lifespan. This would be expected to protect against osteoporosis and bone fracture - a strong bone is resistant to bending and breaking. This suggests that childhood exercise stimulates the skeleton. Short bursts of exercise several times a week would be particularly effective. Older people can still benefit from regular exercise too - to maintain aerobic fitness and conserve bone strength - even if they were not particularly active as children.

Source
Journal of Bone and Mineral Research online November 2007

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