Osteoporosis Prevention: What Kind of Exercise Is Best?

 By Barbara A. Brehm
May 2008
 

        High-impact activities are key to keeping bones healthy and strong.        

Bones like to work hard. The worst thing for bones is a zero-gravity environment, followed by bed rest. A sedentary lifestyle is not so great either — bones follow the "use it or lose it" philosophy. Bones respond to force by laying down more mineral and strengthening their structure to accommodate increased loading. Thinking about the forces produced by physical activities can help you to understand what kinds of exercises cause the greatest adaptation in bone tissue. 

 Exercise that doesn't cause injury

Since inactivity causes bone mineral loss, your No. 1 job is to avoid injury and illness that could interfere with physical activity. This means that, even if high-impact activities, such as running, increase bone strength, you should ignore this recommendation if running worsens or causes problems for you. Check with your healthcare provider if you have any health concerns. A personal trainer can help you to increase your exercise program slowly and gradually, and help you avoid sports injuries.

In the long run, exercise generally helps prevent injury, especially if it improves strength and balance. Research has shown that regular physical activity can help to prevent falls, which can lead to fracture. It is especially interesting that regular physical activity reduces risk of bone fracture with a fall, even when no change in bone mineral density occurs. Regular physical activity seems to improve bone strength, even with no increase in mineral deposition.

If testing shows that you are at very high risk for or have already developed osteoporosis, you may also need medications to help increase bone strength. Sometimes exercise and diet are not enough to prevent or treat osteoporosis. 

 Weight-bearing exercise

Exercise causes the greatest increase in bone strength when mechanical force is placed on the bones, causing a deformation of bone cells. This force appears to be the signal that tells bones that they need to get stronger. Weight-bearing activities such as tai chi, walking, running, many types of sports and weight lifting place more force on the bones than weight-supported activities such as cycling and swimming. 

 Dynamic exercise

Activities that produce constantly changing forces result in more strength improvement than continuous force. Walking and running, with the striking of the foot on the ground alternating with cessation of force, are examples of dynamic exercise when talking about bones. Cross-country skiing, rowing and machines such as elliptical trainers generally do not deliver large changes in force. While these activities provide terrific cardiovascular stimulation, they do not have as great an impact on bone strength. Similarly, wearing a weighted vest to perform low-intensity activity does not provide much bone stimulation. Jumping in a weighted vest, however, exerts a great deal of bone stimulation. 

 High-impact and high-intensity exercise

Lifting heavy weights causes more bone adaptation than lifting lighter weights. Running exerts greater force than walking. Jumping, hopping and skipping provide more impact than running.

Many sport activities provide good bone stimulation. Sport activities often combine running with jumping, and hitting and handling balls, so you get additional impact beyond running, as with soccer, basketball and volleyball. Racquet sports provide impact in many ways. Handball is great, since you receive impact with both hands, and plenty of hard running.

High-impact aerobics classes often include jumping moves in many directions. Step aerobics and running stairs also provide good impact. Plyometric training incorporates high-impact work of variable directions and resistances.

What if these high-impact activities are out of reach for you? Simply increasing walking pace increases the force your body receives as you take steps. So, if you can walk, walk a little faster. If you can walk fast, add a few steps of slow jogging. Take the stairs more quickly. Add heavier weight to your workouts as you are able. 

 Bones need a healthy environment

To build bone strength, you must consume adequate calories and protein, and enough calcium, potassium, magnesium, and vitamins D and K. Plenty of fruits and vegetables provide good nutrition, and help build a good environment for bone growth. Avoid smoking, excessive alcohol and excessive protein intake. Limit salt and empty calories.

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Barbara A. Brehm, Ed.D., is professor of exercise and sport studies at Smith College, Northampton, Mass.

 

Article found on www.fitnessmanagement.com.