Exercise: A Prevention and Treatment for Osteoporosis and Injurious Falls in the Older Adult.

Osteoporosis is a major public health problem in persons over the age of 65, and it leads to approximately 250,000 hip fractures per year. Contributing risk factors for osteoporosis and hip fractures in the aging population include insufficient nutrient intake, inadequate dietary calcium, muscular weakness, decreased physical activity, and changes in hormonal homeostasis. Physical activity especially plays an important role in the prevention of falls and fractures. Physically active older adults with greater muscular strength experience fewer and less injurious falls than older people who are inactive. The effects of physical activity on bone strength and metabolism have only recently been investigated. When bone is mechanically stimulated, the cells respond by producing many local hormones and growth factors, including prostaglandin E₂ (PGE₂), a mediator of bone modeling and remodeling. Current research continues to show that physical activity significantly affects the geometry and architecture of bone as well as increasing bone mineral density, all of which contribute to an increase in bone strength. [ABSTRACT FROM AUTHOR]