WEDNESDAY, Aug. 15 (HealthDay News) -- Engaging in more than two hours of physical activity per week appears to help pre-menopausal women maintain healthy bones, new research suggests.

The finding is based on the impact that even small amounts of exercise seem to have on curtailing the production of a protein that impedes bone growth, while at the same time increasing the activity of another protein that promotes bone formation.

The study will appear in the October issue of the Journal of Clinical Endocrinology and Metabolism.

"Physical activity is good for bone health and results in lowering sclerostin -- a known inhibitor of bone formation -- and enhancing IGF-1 levels, a positive effector on bone health," study author Mohammed-Salleh Ardawi, a professor at the Center of Excellence for Osteoporosis Research and the faculty of medicine at King Abdulaziz University in Saudi Arabia, said in a journal news release.

The authors note that sclerostin, a hormone, works by migrating to bone surfaces, where it impedes bone cell creation. IGF-1 is shorthand for insulin-like growth factor-1, a hormone that promotes growth.

For this finding, researchers tracked 120 pre-menopausal women for an eight-week period. About half of the women were engaged in a supervised physical-activity routine, while the other half were not.

Women who had participated in more than two hours of activity per week were found to have "significantly" lower sclerostin levels and higher IGF-1 levels.

"Physical-activity training is conceptually simple and inexpensive, and can serve practical purposes including reducing the risk of low bone mass and osteoporosis, and, consequently, fractures," Ardawi said. "Our study found that even minor changes in physical activity were associated with clear effects on serum levels of sclerostin, IGF-1 and bone-turnover markers."

More information

For more on exercise and bone health, visit the U.S. National Institutes of Health.

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