Low-impact exercise may boost women's bone mass

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Low-impact exercise may boost women's bone mass

By Amy Norton

NEW YORK, Oct 29 (Reuters Health) - Aerobic exercise can increase women's

bone density, and it need not be a high-impact regimen to work, new research

shows.

In fact, experts' recommendations for general health--walking for about 30

minutes a day, a few days a week--is enough to lend the bones a hand,

A. Kelley, of the MGH Institute of Health Professions in Boston, an academic

affiliate of Massachusetts General Hospital.

In a review of 24 studies on aerobic exercise and bone mineral density in

women, Kelley's team found that, on average, regular exercisers saw about a

2% bone mass gain over non-exercisers.

Whether the modest gain translates into a lower risk of the bone-thinning

disease osteoporosis and its associated fractures is unclear, Kelley told

Reuters Health. However, he added, because exercise improves balance and

coordination, it could lower older women's odds of falling, which would

provide benefits beyond any boosts in bone mass.

Kelley presented the study findings last week in Atlanta, Georgia, at the

annual meeting of the American Public Health Association.

Kelley's team analyzed studies that followed women aged 18 and older, the

majority of whom were sedentary. In each study, some women were assigned to

an aerobic exercise regimen that lasted at least 16 weeks.

Walking was the most common form of exercise used in the studies, Kelley

said. On average, women walked about a half-hour, 3 days a week.

Overall, women who exercised gained close to 0.4% in bone mineral density in

the lower spine, while non-exercisers saw a decrease of nearly 2%.

Exercisers also saw a 1.4% gain in the thighbone, while non-exercisers

recorded a loss of about 0.6%.

The benefits were similar among premenopausal and postmenopausal women,

Kelley noted.

Exercise helps strengthen bones because it forces them to bear weight.

Accordingly, some research shows that exercise that requires more

weight-bearing--such as high-impact activities like running--provides the

greatest benefits to bone.

" But then there's the practical part of getting people to stick with it, "

Kelley pointed out.

" Our adherence to physical activity programs is abominable, " he added.

So the good news from this study is that the most popular form of exercise

in the US--walking--can give a lift to bone mass, according to Kelley.

Since strength training with weights also helps bone density, he added, the

ideal exercise plan includes aerobics and weights.