Physical Activity and Bone Health: Strategies for Exercise Prescription and Osteoporosis
By Jennifer Green, B.S.
|Jennifer Green, NCHPAD Visiting Information Specialist|
While the exact cause of osteoporosis is still under investigation, researchers do know that the normal bone remodeling process, also known as bone turnover, is being disrupted. There are a variety of risk factors, both modifiable and non-modifiable, which contribute to the development of brittle or weak bones. Modifiable risk factors include low calcium intake, tobacco use, sedentary lifestyle, excessive alcohol consumption, and corticosteroid medications. Uncontrollable risk factors consist of female gender, old age, race (you are at greater risk if you are Caucasian or of Asian descent), family history, frame size (men and women who are exceptionally thin or have small body frames are at high risk), increased thyroid hormone, and medical conditions and procedures that affect bone health, such as Crohn's disease and gastroectomies. So, if you have osteoporosis, low bone density, or are at risk for developing this disease, how can you reduce your risk of fractures that can potentially result in the loss of mobility and independence?
The answer is simple - exercise!
Physical activity is essential for bone health. Research has proven that exercise may reduce the risk for osteoporotic fractures by enhancing the peak bone mass achieved during growth and development, by slowing the rate of bone loss with aging, and/or by reducing the risk of falls via benefits in muscle strength and balance. Physical activity plays a prominent role in treatment and prevention of osteoporosis.
When creating an exercise program for individuals with low bone density or osteoporosis, we have to consider the two populations separately; those who are at risk for osteoporosis (defined as having ≥1 risk factor for the disease) and those with osteoporosis. An exercise prescription for persons at risk must focus on the preservation of bone health, while a program for those with the disease should follow recommendations to prevent disease progression.
Individuals who are at risk for osteoporosis should apply the following exercise prescription guidelines set by the American College of Sports Medicine to preserve bone health. It is recommended that these clients participate in weight-bearing cardiovascular training 3-5 days per week at a moderate to high intensity. Weight-bearing aerobic training can include stair climbing, walking, and jogging. Research has shown that effective osteogenic, or bone-forming, exercise prescriptions should include movements that result in high strain rates and high rates of force in directions that bone is unaccustomed to. In other words, physical activities such as agility drills and plyometrics have been shown to have positive effects on bone density, especially in younger participants and should also be included as part of the aerobic training portion of an exercise prescription. Strength training should also be included 2-3 days per week at a moderate (60%-80%, 1-RM, 8-12 repetitions) to high (80%-90%, 5 to 6 repetitions for resistance exercise) intensity. These clients should try to include a combination of strength training and cardiovascular training for at least 30-60 minutes per day.
When training individuals with osteoporosis, the following recommendations should be used when creating an exercise prescription in order to help prevent disease progression. It is suggested that these individuals perform weight-bearing aerobic activity 3-5 days/week at a moderate intensity (40% to <60% Vo2R or HRR). Strength training is also recommended for this group 2-3 days per week at a moderate intensity; however, some individuals, depending on fitness level, may be able to endure more intense exercise. Just as in the prescription for preserving bone health, it is recommended to include a combination of aerobic and strength training for at least 30-60 minutes per day.
Just as in any population, there are special considerations that we must consider as exercise professionals. For those who have osteoporosis, there are currently no established contraindications; however, there are general recommendations that suggest prescribing a program with moderate-intensity exercises that do not cause or exacerbate pain. Exercises that involve explosive movements or high impact should be avoided in those with the disease, as well as exercises that include twisting, bending, or compression of the spine. If you are creating an exercise program for older men and women, it is important to include balance training. Exercises that help to improve balance and coordination can be important tools in fall prevention - a problem that is prevalent in this population.
Just as in any special population, there is no one-size-fits-all prescription. Osteoporosis and low bone density have such a diverse range of severities that it is essential to modify these recommendations to each of your clients individually. Exercise prescription is a science, and as trainers and exercise specialists, we need to be tailoring the guidelines to our clients in order for them to yield the best results. The research is clear when it says exercise can improve bone health. With a combination of effective exercise programming and risk factor education, exercise professionals can help spread the word of the benefits of exercise in the preservation of bone health, as well as the prevention of disease progression.
Osteoporosis. (2009). Retrieved February 23, 2010, from http://www.mayoclinic.com/health/osteoporosis/DS00128
Osteoporosis: What is it? (2008). Retrieved February 23, 2010, from http://www.nof.org/osteoporosis/index.htm
Petit, M. A., Hughes, J. M., & Warpeha, J. M. (2010). Exercise prescription for people with osteoporosis. ACSM resource manual for guidelines for exercise testing and prescription (6th ed., p. 635) Baltimore: Lippincott Williams & Wilkins.
Thompson, W. R., Ph.D., FACSM, Gordon, N. F., MD, Ph.D., MPH, FACSM, & Pescatello, L. S, Ph.D., FACSM (Eds.). (2010). ACSM's guidelines for exercise testing and prescription (8th ed.). Baltimore: Lippincott Williams & Wilkins.
Please send any questions or comments to Jennifer Green at firstname.lastname@example.org.