Health Information

Exercise and Bone Health

PDF Version of this Document

October 2006

Exercise Information Packet

Revised 2004

Excerpt from: Bone Health and Osteoporosis: A Report of the Surgeon General Chapter 6: Determinants of Bone Health

Physical Activity, Body Weight, and Bone Health: What the Evidence Tells Us
  • Physical activity is important for bone health throughout life.
    • Depending on age, it may help increase or preserve bone mass.
    • It may also help reduce the risk of falling.
  • All types of physical activity can contribute to bone health.
    • Activities that are weight bearing or involve impact are most useful for increasing or maintaining bone mass.
    • Some activities that are not weight bearing or are low impact may help improve balance and coordination and maintain muscle mass, which can help prevent falls.

Physical activity of all kinds has overall benefits to health and weight maintenance. Regular physical activity lowers risk factors for cardiovascular disease, colon cancer, and type 2 diabetes, and helps to control blood pressure (USDA 2000). Physical activity plays an important role in skeletal health because bone mass is responsive to the mechanical loads placed on the skeleton.

Background: Why Focus on Physical Activity?

The body constantly monitors the strain on bones caused by muscle action, and any substantial increase in these forces signals the need to build more bone. Conversely, reductions in biomechanical forces from lower activity levels or loss of muscle mass (sarcopenia) signals less need for bone, which leads to the elimination of bone. The latter process may be worsened by estrogen deficiency, which appears to reduce the sensing of biomechanical strains by bone cells (Riggs et al. 2002).

Physical activity has been identified as one of the Leading Health Indicators in the Healthy People 2010 health objectives for the Nation during the next decade. It is one of the most important controllable lifestyle changes to help prevent (or reduce the risk of) a number of chronic conditions, including heart disease, diabetes, and some cancers. It also helps with weight control and the lessening of symptoms related to arthritis (USDHHS 1996).

Many adult Americans do not engage regularly in leisure-time physical activity. The participation by both men and women declines with age, with women being consistently less active than men (Schiller et al. 2004). The same problem exists for children. Many children become far less active as they pass through adolescence. Only half of those age 12 to 21 exercise vigorously on a regular basis and 25 percent report no exercise at all (Gordon-Larsen et al. 1999). Children may find it difficult to get daily physical activity in schools. While most schools have requirements for physical activity of some kind, only 8 percent of elementary schools, 6.4 percent of middle/junior high school, and 5.8 percent of senior high schools provide physical education on a daily basis (SHPPS 2001). At the other extreme, some girls and young women, especially those training for elite athletic competition, exercise too much, eat too little, and as a result develop delayed puberty or amenorrhea (cessation of menstrual periods). These girls are at risk for low bone mass and fractures (Warren 1999). One of the national health objectives for 2010 is to increase to 30 percent the proportion of adults who perform, more than 2 days per week, physical activities that enhance and maintain muscular strength and endurance (USDHHS 2000). Only 12 percent of people age 65 to 74 and 10 percent of those over age 75 meet that objective, underscoring the need for programs that encourage older adults to incorporate strength training and regular physical activity into their lives (Kruger et al. 2004).

To encourage increased levels of physical activity among all age groups, "Physical Activity and Health: A Report of the Surgeon General" recommends a "minimum of 30 minutes of physical activity of moderate intensity (such as brisk walking) on most, if not all, days of the week" (USDHHS 1996). Children and adolescents should aim for at least 60 minutes of physical activity per day (USDA 2000). In addition to helping achieve healthy weight and avoid chronic diseases like heart disease and diabetes, this type of physical activity can benefit skeletal health by building muscle mass and promoting balance and coordination, which may help individuals avoid falls and/or minimize the impact if a fall does occur. But the skeleton responds preferentially to strength training and short bouts of high-load impact activity (such as skipping or jumping), both of which improve bone mass and strength. In light of this, "Physical Activity and Health: A Report of the Surgeon General" also recommended that adults supplement their cardiorespiratory endurance activity with strength-developing exercise at least two times per week (USDHHS 1996).

Excerpted from: U.S. Department of Health and Human Services. Bone Health and Osteoporosis: A Report of the Surgeon General. Rockville, MD: U.S. Department of Health and Human Services, Office of the Surgeon General, 2004, pages 122-124.

Revised 2004

Excerpt from: Bone Health and Osteoporosis: A Report of the Surgeon General Chapter 7: Lifestyle Determinants to Promote Bone Health

The foundation of a good physical activity regimen involves at least 30 minutes (adults) or 60 minutes (children) of moderate physical activity every day. This regimen can and should involve a variety of activities. Some can be routine activities like walking or gardening. Others may occur more infrequently and differ from day to day and week to week, such as dancing, aerobic classes, biking, swimming, tennis, golf, or hiking. However, it is clear that physical activity to specifically benefit bone health should involve loading (stressing) the skeleton. As a result, weight-bearing activities such as walking should be included in an optimal physical activity regimen to benefit the musculoskeletal system. Moreover, the evidence suggests that the most beneficial physical activity regimens for bone health include strength-training or resistance-training activities. These activities place levels of loading on bone that are beyond those seen in everyday activities; examples include jumping for the lower limbs and weight lifting or resistance training for the lower and upper skeleton. Finally, while a focus on activities that build or maintain bone strength is appropriate and necessary, many older individuals will remain at high risk of fracture. For these individuals, balance training can provide the added benefit of helping to prevent potentially injurious falls.

The evidence does not lead to a specific set of exercises or practices but rather a set of principles that can be applied and varied according to the age and current physical condition of an individual. Many of these principles have been reviewed by expert panels of the American College of Sports Medicine (ACSM) (Kraemer et al. 2002, ACSM 1998a, ACSM 1998b) and they lead to the following suggestions for the frequency, intensity, length, and type of physical activity regimens to benefit bone health for individuals of all ages:

  • Since continued physical activity provides a positive stimulus for bone, muscle, and other aspects of health, a lifelong commitment to physical activity and exercise is critical.
  • Ending a physical activity regimen will result in bone mass returning to the level that existed before the activity began. Since repetitive programs of physical activity may be discontinued due to lack of motivation or interest, variety and creativity are important if physical activity is to be continued over the long term.
  • Physical activity will only affect bone at the skeletal sites that are stressed (or loaded) by the activity. In other words, physical activity programs do not necessarily benefit the whole skeleton, although any type of activity provides more benefit to bone than does no activity at all.
  • For bone gain to occur, the stimulus must be greater than that which the bone usually experiences. Static loads applied continuously (such as standing) do not promote increased bone mass.
  • Complete lack of activity, such as periods of immobility, causes bone loss. When it is not possible to avoid immobility (e.g., bed rest during sickness), even brief daily weight-bearing movements can help to reduce bone loss.
  • General physical activity every day and some weight-bearing, strength-building, and balance-enhancing activities 2 or more times a week are generally effective for promoting bone health for most persons.
  • Any activity that imparts impact (such as jumping or skipping) may increase bone mass more than will low- and moderate-intensity, endurance-type activities, such as brisk walking. However, endurance activities may still play an important role in skeletal health by increasing muscle mass and strength, balance, and coordination, and they may also help prevent falls in the elderly. Endurance activity is also very important for other aspects of health, such as helping to prevent obesity, diabetes, or cardiovascular disease.
  • Load-bearing physical activities such as jumping need not be engaged in for long periods of time to provide benefits to skeletal health. In fact, 5 to10 minutes daily may suffice. Most adults should begin with weight-bearing exercise and gradually add some skipping and jumping activity. Longer periods (30 to 45 minutes) may be needed for weight training or walking/jogging. Those who have been inactive should work up to this amount of time, gradually using a progressive program, e.g., start with shorter times and easier activities (light weights or walking) and then increase time or intensity slowly (by no more than 10 percent each week) in order to avoid injury.
  • Physical activities that include a variety of loading patterns (such as strength training or aerobic classes) may promote increased bone mass more than do activities that involve normal or regular loading patterns (such as running).

These fundamental principles can be used to develop age-specific regimens, as outlined in the sections that follow.

Physical Activity for Children and Adolescents

For children over age 8 and adolescents, a bone-healthy program of physical activity could include the following:

  • At least 60 minutes of moderate intensity, continuous activity on most days, preferably daily. This level of activity can help achieve a healthy body weight and lower the risk of other diseases such as cardiovascular disease and diabetes (USDHHS 1996, USDA 2000, USDHHS 2000, IOM 2002).
  • Inclusion of weight-bearing and short, intense impact activities such as basketball, gymnastics, and jumping as part of this regular activity program.
  • Performance of weight-bearing activities that increase muscle strength, such as running, hopping, or skipping. The best activities work all muscle groups. Examples include gymnastics, basketball, volleyball, bicycling, and soccer. Swimming, while highly beneficial to many aspects of health, is not a weight-bearing activity and thus does not contribute to increased bone mass.
Table 7-6. Weight-Bearing Exercise for Kids and Teens

Exercise helps build bone and weight-bearing exercise is particularly helpful in this task. Weight-bearing exercise includes any activity in which your feet and legs carry your own weight. Here are some examples of weight-bearing exercise that can help you build strong bones:

  • Walking
  • Running
  • Jumping
  • Jumping rope
  • Dancing
  • Climbing stairs
  • Jogging
  • Aerobic dancing
  • Hiking
  • Inline skating/ice skating
  • Racquet sports, such as tennis or racquetball
  • Team sports such as soccer, basketball, field hockey, volleyball, and softball or baseball

Source: NICHD 2004.

 

Physical Activity for Adults

Adults should strive to get at least 30 minutes of physical activity on most days, preferably daily (USDHHS 1996, USDA 2000, USDHHS 2000, IOM 2002). As part of that regular physical activity program, the following can help enhance bone health:

  • For those individuals who can tolerate impact activities, a simple, 10-minute program of physical activity that incorporates 50 3-inch (8-centimeter) jumps per day.
  • A progressive program of weight training that uses all muscle groups, with the amount of weight lifted increased gradually over time.
  • A jogging or stair-climbing program for those who cannot tolerate higher impact physical activity.
  • Active recreational activities such as tennis, hiking, or basketball.

In addition, it is advisable for adults to try to find ways to add extra weight-bearing exercise into everyday activities. For example, consider parking farther away in the parking lot or taking the stairs instead of the elevator.

General recommendations for physical activity in adults are shown in the pyramid in Figure 7-2, with the base of the pyramid being 30 minutes or more of moderate physical activity on most, preferably all, days of the week. It is also recommended that weight-bearing exercises and strength and balance training be added as a part of regular physical activity (Nelson 2002, Seguin and Nelson 2003). Lifestyle activities such as walking, gardening, and raking leaves can also be a valuable part of regular physical activity (USDHHS 1996).

It is important to begin any physical activity program slowly and to consider previous activity levels. Those who have been inactive should begin with 5 to 10 minutes of activity per day, and a pre-exercise evaluation by a physician may be advised. Those who are more fit can increase physical activity levels to 20 to 30 minutes of moderate activity at a higher heart rate (60-85 percent of maximum heart rate). Generally, it is advisable to increase activity levels by no more than 10 percent each week to avoid injury. For example, those who begin with 15 minutes per day can progress to 17 minutes the second week, and so on.

Finally, adults should consult a physician or physical therapist if orthopedic conditions like arthritis, functional limitations, or other medical conditions make these physical activity guidelines difficult or unsafe to follow.

A pyramid chart showing general recommendations for physical activity in adults.

 

Physical Activity for Older Adults

Most elderly individuals should strongly consider engaging in regular physical activity. Physical activity is the only single therapy that can simultaneously improve muscle mass, muscle strength, balance, and bone strength. As a result, it may decrease the risk of fractures, in part by reducing the risk of falling. In fact, fall risk reduction may be the biggest benefit of physical activity for the elderly.

The following guidelines should be used to maximize the potential fall-prevention benefits of physical activity in the elderly:

  • Physical activity needs to be of sufficient intensity to improve muscle strength, since poor muscle strength is a known risk factor for falls. Strength or resistance training is best for building muscle, but even aerobic endurance activity can yield some improvements in muscle strength.
  • Improving balance can be an important component of any physical activity program designed to decrease falls. This program may include balance training exercises or a movement activity such as Tai Chi. Any activity that requires weight bearing and challenges the postural system can improve balance and potentially help reduce falls.
  • Physical activity must be performed on average 3 times per week for 30 to 45 minutes per session for at least three months for strength and balance benefits to be realized, and it must be continued if benefits are to be maintained.

Those who suffer a fall that requires a visit to a health-care provider or an emergency room should ask for a fall risk assessment that includes a program of physical activity. Physical activity is most effective if delivered as a part of a comprehensive fall-prevention program.

Illustrations showing strength training exercises and instructions.

 

Physical Activity for Those With Fragility Fractures

Individuals who have already experienced osteoporotic fractures should avoid certain types of physical activities and exercises. For example, those who have had vertebral fractures may need to avoid activities that flex the spine.

Excerpt from The Surgeon General's report showing high-impact, low-impact and non-impact exercises. Figure 7-4, Excerpt from The Surgeon General's report showing resources for strength training in older adults.

For more information on the resources listed in Figure 7-4 go to:

Excerpted from: U.S. Department of Health and Human Services. Bone Health and Osteoporosis: A Report of the Surgeon General. Rockville, MD: U.S. Department of Health and Human Services, Office of the Surgeon General, 2004, pages 171-177.

Revised October 2006

Additional Resources

Recognizing the National Bone and Joint Decade 2002-2011

NIH Osteoporosis and Related Bone Diseases ~ National Resource Center

2 AMS Circle
Bethesda,  MD 20892-3676
Phone: 202–223–0344
Toll Free: 800–624–BONE
TTY: 202-466-4315
Fax: 202-293-2356
Email: NIAMSBoneInfo@mail.nih.gov
Website: http://www.niams.nih.gov/Health_Info/bone/default.asp

The NIH Osteoporosis and Related Bone Diseases ~ National Resource Center provides patients, health professionals, and the public with an important link to resources and information on metabolic bone diseases. The mission of NIH ORBD~NRC is to expand awareness and enhance knowledge and understanding of the prevention, early detection, and treatment of these diseases as well as strategies for coping with them.

The NIH Osteoporosis and Related Bone Diseases ~ National Resource Center is supported by the National Institute of Arthritis and Musculoskeletal and Skin Diseases with contributions from:

The National Institutes of Health (NIH) is a component of the U.S. Department of Health and Human Services (DHHS).

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