The independent and additive effects of exercise training and estrogen on bone metabolism

Osteoporosis is a bone disease associated with reduced bone mineral density resulting in debilitating bone fractures. This disease is recognized as a serious health problem, affecting more than 20 million persons in the United States and causing about 1.3 million hip fractures annually. The treatment costs of osteoporotic fractures present a significant burden to the health care system in the United States. It is important to find effective interventions for building bone and for preventing bone loss in postmenopausal women. Estrogen replacement therapy (ERT) is considered by leading experts to be the most important intervention for both the prevention and treatment of osteoporosis because it increases bone density and decreases fracture rates. The osteogenic stimulus provided by load-bearing exercise indicates it is an important Lifestyle factor that can be used for prevention of bone loss. Resistance exercises may be especially effective stimuli, as specific localized sites are loaded. Additional benefits include increased muscular strength, coordination, and balance, which could decrease risk for falling. Recently, it has been shown that exercise and ERT can have additive effects on bone. The purpose of this review is to examine the potential benefits of ERT, weight-bearing exercise and the combination of these two treatments for skeletal health and osteoporosis prevention in postmenopausal women.