Exercise

Exercise plays an important role in building and maintaining bone strength.  Just like muscles, bones respond when they are “stressed,” in other words, when they are forced to bear more weight than they are used to. This can be achieved by “weight bearing” or impact exercises such as walking, running, lifting weights, jumping, or dancing. Low impact or “non-weight bearing” exercises, such as cycling or swimming will not have the same ‘loading’ effect on bones, but are nevertheless excellent for overall health, and improve muscle strength.

A regular, well-structured exercise regimen is a necessary component in osteoporosis prevention. It can also help protect against osteoporosis-related fractures, and aid in rehabilitation. Clearly, all exercise regimens should be appropriate to individual capabilities and, in people with osteoporosis or other medical conditions, should be specially targeted or under professional supervision.

For more specific information see section Exercise recommendations.

Below is an outline of the key benefits of exercise in different age groups. The information is summarized from the IOF report Move it or Lose it: How Exercise helps to build and maintain strong bones, prevent falls and fractures, and speed rehabilitation.

Exercise builds bone in children

How long a house will last depends on how strong the foundation is. Likewise, how long bones stay healthy depends on how well they were made to begin with.

Most people reach their “peak bone mass” in their 20s. This is when bones have achieved their maximal density and strength. After peak bone mass is reached, bone density remains stable during adulthood, and then begins to decline. Although nutrition – especially sufficient calcium, vitamin D and protein - are critical for bone development, recent studies have shown that in laying down the bone foundation that will serve for a lifetime, exercise is just as important. This is true throughout childhood and adolescence, but especially important around the growth spurt at puberty (1).

For example, it has been shown that the most physically active young girls gain about 40% more bone mass than the least active girls of the same age (2). This extra bone contributes to peak bone mass, and should give these more active girls an advantage in later life. In girls, the bone tissue accumulated during the ages of 11 to 13 approximately equals the amount lost during the 30 years following menopause (3).

Exercise helps maintain bone in adults and the elderly

In adults exercise plays a key role in preventing bone loss and maintaining muscle strength. Perhaps nowhere is this more obvious than in people who are forced to maintain bed rest. In a study to investigate the effects of long-term space travel, healthy, young volunteers were prevented from using their muscles for extended periods. After spending months lying flat, not doing any exercise, they experienced weak muscles and bone loss. Up to 15% of their bone mineral density was lost in as little as three months (4).  Such studies demonstrate that exercise and bone maintenance are inextricably linked.

Targeted exercise in particular can effect bone strength and reduce the risk of fractures. Studies from the USA and Japan, found that when older, postmenopausal women used small weights to strengthen their back muscles over a period of about two years, ten years down the road, they had stronger back muscles than their peers who did not exercise. Their bones were stronger too, particularly their vertebrae. But what is probably even more important, these back strengthening exercises reduced the chance of getting a fracture by almost three-fold (5). In these women, aged from 58 to 75, only about 11% of those who exercised were found to have at least one vertebral fracture, while just over 30% had suffered a fracture in the group that had not used the exercise regimen.

Women who had not taken part in the back exercise program were also about twice as likely to have a compression fracture in the spine, or have “wedged” vertebrae.

Exercise helps posture and balance

Though a person with osteoporosis has a much greater risk of suffering a bone fracture than someone with normal bone mineral density, it is often a fall that causes the fracture. This puts elderly people at even greater risk of fracturing a bone because they tend to fall more often. In fact, every year about two out of five (40%) people over 65 fall at least once.  So how can falls be prevented? Following treatment for an injurious fall, older people should be offered multidisciplinary assessment to identify and address future risk, and individualized intervention aimed at promoting independence and improving physical and psychological function. In addition to an assessment of home hazards, visual impairment and medication, it is essential that strength and balance training are offered (6).

Numerous studies have shown that people with better posture, better balance, and greater muscle power are much less likely to fall and are therefore less likely to be injured. On the other hand, those with a more sedentary lifestyle are more likely to have a hip fracture than those who are more active. For example, women who sit for more than nine hours a day are 50% more likely to have a hip fracture than those who sit for less than six hours a day (7).

Because of these findings, many research groups have been investigating the benefits of exercise in the elderly as a means to improve their coordination, strength and balance.

When data is pooled from these studies it shows that in women over 80 years old, an individually tailored exercise regimen that incorporates progressive muscle strengthening, training for balance, and a walking plan, can reduce the overall risk of falling by about 20%, and cut serious injury-sustaining falls by just over 30% (7).

The balance aspect of this training may be key. A study has shown, for example, that patients practicing Tai Chi, an ancient Chinese martial art that focuses on balance, fall only half as much as their peers. This significant improvement was achieved after only 15 weeks, during which the patients received one Tai Chi lesson per week with an instructor and were asked to practice twice daily for 15 minutes on their own.

This graph demonstrates that people over 80 who practice regular, tailored exercise have 20% fewer falls and approximately 35% fewer injurious falls in comparison to their sedentary counterparts. (Ref. Wolf SL et al. 1996. J Am Geratr Soc 44:489-497)

Patients who peformed Tai Chi twice daily had an impressive further risk reduction of almost 50% (Ref. Wolf SL et al. 1996. J Am Geratr Soc 44:489-497)

Exercise aids rehabilitation

Exercise can also play a crucial role in rehabilitation. Muscle strengthening exercises can help to rebuild bone in those who have developed osteoporosis, and it can also provide relief from one of the most debilitating symptoms of osteoporosis: pain.

Chronic pain is perhaps most problematic in people with kyphosis, or curvature of the spine most often due to osteoporotic fractures of the vertebrae. Kyphosis causes loss of height, poor posture, and a shift in the center of gravity. Because of these changes, people with kyphosis have a greater risk of falling and possibly having a fracture. In the worst cases, the curvature of the spine is so severe that the rib cage is pressed down against the pelvis. This most often happens when vertebral fractures lead to an additional loss of height. Forced into this posture, patients can suffer chronic, severe pain, and can also have trouble breathing. Exercise can help relieve the pain and some of the symptoms of kyphosis. By strengthening the muscles in the back, the spine can be brought more upright. This has been shown to increase mobility and reduce pain (8). This type of therapy can greatly improve the quality of life of the patient.

Hip fractures may be the most serious complication that can arise from osteoporosis. More than 95% of patients require surgery to repair their hip fracture, and of these, fewer than one-third will regain normal functioning, and a further one-third have to give up independent living and need constant care. Recent studies have shown that intensive exercise training can lead to improvements in strength and function in elderly patients who have had hip replacement surgery (9). Patients who received the exercise therapy were significantly better at a variety of daily living fundamentals, such as getting up, walking, climbing stairs and maintaining posture. For example, they walked on average 50% faster and climbed stairs about 30% faster than patients who did not receive the exercise regimen. Emotionally, patients who had received the exercise therapy were less distressed by their overall condition than patients who did not, although both groups of patients were equally as fearful of falling (9).