Good news for women: a little exercise goes a long way toward bone health.

According to new research, just two or more hours of physical activity per week appears to help pre-menopausal women maintain healthy bones. Women in the study who engaged in physical activity significantly reduced a known inhibitor of bone formation called sclerostin.
The study appeared in the October, 2012, issue of the Journal of Clinical Endocrinology and Metabolism.
According to 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, "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."
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.
The team examined 1,235 premenopausal women for the study. They followed 58 women during an 8-week course of physical activity training and compared them with 62 women who acted as controls.
All study participants underwent a medical examination and had their measurements taken for bone mineral density, bone turnover markers, serum sclerostin and IGF-1.
The team found that women who engaged in 2+ hours of physical activity per week had considerably lower levels of serum sclerostin than those who had less than 2 hours of physical activity per week. However, those who regularly exercised had 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.