Older women with thinning bones who exercise regularly have sustained improvements in their balance and walking speed that may protect them from fractures and even extend their lives, new research shows.

The researchers found that just 20 minutes of at-home exercise daily, interspersed with six months of supervised weekly training every year, over the course of five years helped increase women's gait stability and cut their risk of fracture by 32 percent.

The improvements persisted for two years after the exercise program ended, with exercisers also being at lower risk of sustaining hip fractures or dying during follow-up, Dr. Raija Korpelainen of the department of sports and exercise medicine at Oulu Deaconess Institute in Oulu , Finland , and colleagues found.

While exercise has been shown to help prevent falls in healthy older people, Korpelainen and colleagues note in the Archives of Internal Medicine, less information is available on the effectiveness of exercise for older women with the bone-thinning disease osteoporosis.

The researchers had originally conducted a 30-month trial of an exercise intervention in 160 women with osteopenia, meaning they had some loss of bone density but not enough to constitute osteoporosis. They found that the women who exercised walked more quickly and performed better on other measures of strength and stability than the women who didn't exercise. In the current study, they report on a seven-year follow-up of participants in that study.

Fifty-five women in the exercise group and 45 in the control group were available for the final follow-up measurements. During follow-up, 17 hospital-treated fractures occurred in the exercisers, compared to 23 in the control group. None of the women in the exercise group had hip fractures during follow-up, while there were five hip fractures among the control group women.

Among all the women in the study, those who had engaged in moderate physical activity throughout their lives were 78 percent less likely to sustain a fracture during follow-up.

While the exercisers had maintained their baseline walking speed over the course of the follow-up period, the control group showed a significant decline over time. But both groups saw a similar decline in bone mineral density during follow-up.

One of the exercise group participants, representing 1.2 percent of the follow-up group, had died seven years into the study, compared to eight, or 10.5 percent, of the control group. But the small size of the study, the researchers say, "limits the conclusions that can be drawn" about whether exercise actually reduced mortality.

The researchers also note that fractures in the control group were located closer to the core of the body (for example, in a hip rather than a knee) than the fractures in the exercise group, "indicating that the type of fall may have been different in the exercisers."

The improvements seen in gait and other measurements of physical capacity in the exercise group may have allowed them to fall in a way that was less likely to result in serious injury, they suggest.

Even small declines in strength and stability can significantly impair older people's ability to perform activities of daily living, such as getting out of bed, the researchers note. "Many elderly people live just beyond the threshold of the capacity needed for such tasks," they add. "These results suggest that these women may have had an increase in performance capacity reserve large enough to prevent loss of independence and future fractures."

"Regular daily physical exercise," the researchers conclude, "should be recommended to elderly women with osteopenia."

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