EXERCISE AND OSTEOPOROSIS
“A third of all women and one in twelve men will suffer an osteoporotic fracture at some time in their lives”
Recommended activities
For young individuals including pre-menopausal women
Jumping or skipping (50 x daily) Field or racquet sports (3 x a week)
High impact dancing (Irish, Scottish or tap, 3 x a week)
For post-menopausal women and older men
Weight-training (using high resistance and few repetitions)
Intermittent jogging (for 10-20 minutes 3 x a week)
Stair-climbing (10 flights a day)
Jogging (for 10-20 minutes 3 x a week) Exercise classes (with a variety of weight-bearing activities including some with brief high impact)
Contraindicated activities
Spinal flexion should be avoided. This includes toe-touching with straight knees, some yoga exercises and sit-ups. There are ways of improving abdominal strength without doing sit-ups.
Non-effective activities
Non-weight-bearing forms of exercise such as swimming and cycling, which are excellent forms of exercise for reducing the risk of cardiovascular disease or dia- betes, are not effective for reducing the risk of osteoporosis. Nor does walking more than 10 minutes a day provide any extra benefit.
shown that BMD can be improved signifi- cantly. Most of these studies have been done in post-menopausal women but a few studies have confirmed that men also benefit (3). Many studies in oestrogen- deplete women have also shown success- ful increases in BMD so a high oestrogen level is evidently not essential for a response. The increases relative to the control group in the studies are on aver- age one to three per cent depending on the study but there is variation in the response and some individuals will improve by as much as 10%. Those with the most sedentary lifestyles and the low- est initial BMD are likely to improve the most with exercise. These increases are relevant for protection against future fracture risk. However it is important that physical activity is maintained or the gains will gradually be lost again. It is also possible that the effects of exercise on bone strength are actually greater than the increase implied by the increase in bone mineral density as BMD is related to bone strength but is not exactly the same thing.
Exercise advice Pre-menopause In pre-menopausal women 50 jumps per day was effective for increasing BMD at the hip by 3-4% (4). This is a feasible form of exercise as it takes only a few minutes to do. Jogging three times a week was also effective for both spine and hip although the improvements were smaller at about 1% (5).
Post-menopause In post-menopausal women, 50 jumps per
day was not effective (4), but exercise classes containing a variety of weight- bearing activities including some jumping were effective (6). Intermittent jogging and stair-climbing were effective for both spine and hip (7) and weight-training was also effective at all sites assessed includ- ing the spine, hip and forearm (8). Weights were lifted using only one side of the body, the other side was the control. The results confirmed the site-specific nature of the stimulus. Large weights (85% of 1 repetition maximum) and few repetitions (3 sets of 8 lifts) were used. Other studies of weight-training have not been effective, despite large increases of 25% or more in muscle strength, perhaps because the weights were too light.
Osteoporotic patients People with osteoporosis should not do any of the exercises listed above. Their skeletons are too fragile to resist the stresses and strains which are the effec- tive stimulus for improving bone strength in more robust individuals. It is however important that they take gentle exercise to maintain physical function and prevent further deterioration. Walking for 10 min- utes daily is recommended. Hydrotherapy, water aerobics and Tai Chi are helpful for improving balance and helping to prevent falls. Back extensor exercises to improve posture, reduce pain, and prevent kypho- sis and further fracture are particularly useful (9).
Potential hazards of physical activity For those with BMD within the normal range, and no history of frequent low- trauma fracture, the hazards of physical
Figure 1: The difference between BMD in healthy and osteoporotic bone
Healthy bone
Osteoporotic bone SportEX 19