Written by Kerri Winters-Stone, Ph.D., FACSM
Osteoporosis, a weakening of the bones causing them to fracture easier, is a disease that most women are familiar with because it’s long been considered a woman’s disease. Even though we now know that men are also vulnerable to osteoporosis, the disease afflicts more women than men largely because women have naturally smaller and lighter skeletons and because women suffer menopause-related bone loss in addition to age-related losses.
Near or at the onset of menopause, typically around age 50, women’s bodies lose the ability to produce normal levels of estrogen, thus estrogen’s protective effect on the skeleton is lost. During the early menopausal years, loss of estrogen can cause bone to be lost two to five times more quickly than loss caused by age alone. While estrogen and/or hormone-replacement therapy (combination of estrogen and progesterone) has been shown to effectively stop menopause-related bone loss, recent health concerns over the use of hormone replacement therapy have made it less popular.
While estrogen levels are one factor that determines the health of the skeleton, many more factors play a role in maintaining bone health. Two of the most important factors are physical activity and nutrition. These factors are no less important after menopause. Physical activity plays a very important role in keeping our bones strong. Many studies have shown that physically active women have higher bone mass than inactive women and that physically active persons experience fewer fractures even if they have osteoporosis. Studies have also shown that when people engage in a certain types and amounts of physical activity (see below), their bone mass may increase, or at least be protected against severe decreases.
Another important role of physical activity is to prevent falls. While bone health is certainly a strong indicator of a person’s fracture risk, falling may be an equally important risk factor for fracture.
Evidence-based guidelines specific to reducing fracture and falling risks have been developed by a group of experts convened to write the American College of Sports Medicine’s Position Stand on Physical Activity and Bone Health. These current exercise recommendations from this publication are as follows.
For Preserving Bone Health in Adulthood
- Mode: Weight-bearing endurance activities (tennis; stair climbing; jogging, at least intermittently during walking), activities that involve jumping (volleyball, basketball), and resistance exercise (weight lifting)
- Intensity: Moderate to high
- Frequency: Weight-bearing endurance activities 3-5 times per week; resistance exercise 2-3 times per week
- Duration: 30-60 minutes/day of a combination of weight-bearing endurance activities, activities that involve jumping, and resistance exercise that targets all major muscle groups
For Elderly Women and Men
Exercise programs for elderly women and men should include not only weight-bearing endurance and resistance activities aimed at preserving bone mass, but also activities designed to maintain balance and prevent falls.
The most effective fall prevention exercise programs in older adults are those that include both moderate to vigorous resistance exercise targeting the lower body and balance exercises. Alternative forms of exercise that focus on dynamic strength and balance, such as Tai Chi, are also effective at reducing falls in older adults.
For individuals with diagnosed osteoporosis, the ACSM Resource Manual suggests the following guidelines for physical activity and resistance training aimed to prevent falls:
- One to three sets with five to eight repetitions of four to six weight-bearing, lower-body strength exercises using body weight as resistance
- Activities performed two to three days/week
- Additional resistance may be applied gradually and conservatively (up to 10 lbs.) with weighted vest
- Therapy bands & rubber tubing may be used to facilitate range-of-motion exercises
- Avoid impact exercise, spinal flexion against resistance, spinal extension, high compressive forces on the spine, quick trunk rotation
When it comes to bone health, a sensible diet is the perfect complement to a physically active lifestyle. The two most important nutrients for the skeleton are calcium and vitamin D. If dietary intake of calcium is chronically inadequate, bone will be lost from the skeleton and it can weaken. Vitamin D keeps bone strong because it facilitates calcium absorption. More recently, research has shown this nutrient is also important for maintaining strong muscles and can help prevent falls. The Food and Nutrition Board of the Institute of Medicine of the National Academies (http://dietary-supplements.info.nih.gov/) recommends the following intake levels for post-menopausal women:
- Calcium: 1200 milligrams/day
- Vitamin D: 10 micrograms/day (400 International Units/day) from ages 51 to 70 (Increase to 15 micrograms/day [600 International Units/day] after age 70)
Menopause marks an important time for women to evaluate their risk of osteoporosis. For women who are concerned about their risk of fracture, physical activity and good nutrition are important strategies to adopt. Following dietary guidelines and practicing a specific exercise program based on ACSM recommendations are bone-smart habits that will help women stay fracture free. We know that bone benefits from exercise are lost when someone stops training, so exercise done to target the bones must be a lifelong commitment. An ACSM-certified fitness professional has the background and training to help develop a comprehensive program that is enjoyable, safe and effective.
1. Kohrt WM, Bloomfield SA, Little KD, Nelson ME, Yingling VR. American College of Sports Medicine Position Stand: physical activity and bone health. Med Sci Sports Exerc. Nov 2004;36(11):1985-1996.
2. Shaw JM, Witzke KA, Winters KM. Exercise for Skeletal Health and Osteoporosis Prevention, ACSM Resource Manual, 4th Edition, Williams & Wilkins Publishers, 2001.
View the full fall 2009 issue of the ACSM Fit Society® Page online.