Senior Exercise (cont.)

Medical Editor:

What happens to bones as we age?

Bones tend to decrease in density as we age, and for some individuals, it can lead to osteoporosis. Osteoporosis is a disease of low bone density and can lead to an increased risk of fracture. According to the National Osteoporosis Foundation, osteoporosis and low bone mass affect 44 million men and women ages 50 and older in the United States, or 55% of the people 50 years of age and older.

The bad news is that osteoporosis is responsible for more than 1.5 million fractures annually, including over 300,000 hip fractures, 700,000 vertebral fractures, 250,000 wrist fractures, and 300,000 fractures at other sites. The good news is that exercise can increase bone density in some older individuals. The precise amount and type of exercise necessary to accrue notable benefits is unknown, but encouragingly, research shows that weight lifting, and even just walking, can increase bone density in the hip and spine. The reason for the benefits may be that weight lifting causes stress on the bones as the muscles contract (which causes the bones to thicken), and the impact of walking also causes stress on the bones, which stimulates them to grow.

In two different studies of weight lifting—one of middle-aged and older men (50-70 years old) who lifted weights three times a week for 16 weeks, and the other of women 40-70 years of age who lifted twice a week for one year—bone density in the leg and back of subjects in both studies increased. There is also some evidence that walking can increase bone density in the hips and lower back, but the recommendation for frequency and intensity of the walking is not clear. What is clear is that exercise does help build or preserve bone density, and so it is recommended that we stay active for the sake of our bones and overall health health.

What happens to our joints as we age?

Many aging adults are susceptible to osteoarthritis (the type of arthritis that affects the bone by wearing down the cushion that pads the space between bones).

In a large study of 439 adults (aged 60 and older) with osteoarthritis who did either aerobic exercise (walking) or resistance exercise (weight lifting) for 18 months, participants in the aerobic exercise group had a 10% decrease on a physical disability questionnaire, a 12% lower score on a knee pain questionnaire, and outperformed non-exercising individuals in the study on the following tests: a six-minute walk test (they walked further); the time it took them to climb and descend stairs; the time it took them to lift and carry 10 pounds; and the time it took them to get in and out of a car. In the weight-lifting, group, there was an 8% lower score on the physical disability questionnaire, 8% lower pain score, greater distance on the six-minute walk, and faster times on the lifting and carrying task and the car task than in the individuals in the study who did not exercise.

Other studies confirm that exercise can improve function for people with arthritis. Make sure to check out the Arthritis Foundation Web site for more information on exercise and in particular, their PACE program (People with Arthritis Can Exercise). They offer exercise videos and water classes all over the country.

Medically Reviewed by a Doctor on 1/24/2014