Juliet's Journal
1 entry, last entry on March 18, 2008
Weight-bearing exercise and bone health
March 18, 2008
I had the opportunity and pleasure of attending the Cooper Institute of Aerobic Research to receive my Physical Fitness Specialist Certification and Health Promorion Director Certification. Dr. Kenneth Cooper spoke at both trainings; an uncommon occurrance, so it was quite a surprise! To learn more about the Cooper Institute, visit their website. The following is from their Health Tips email:
Weight-bearing exercise counteracts bone loss that occurs with aging
By Kenneth H. Cooper, M.D., M.P.H., and Tyler C. Cooper, M.D., M.P.H., with William Proctor
After about age 30, natural bone growth ceases, and steady bone loss begins in various parts of the body. If you don’t act to delay or stop this bone loss, you’re likely to end up with a fragile bone structure by the time you reach your later years.
Fortunately, you can begin to act against this deterioration at any age, and one of the best strategies is to include weight-bearing exercise in your fitness program. What constitutes weight-bearing exercise? Answer: anything that causes your muscles and bones to push or pull against resistance or gravity.
One of the most obvious weight-bearing exercises is brisk walking, or even better, jogging. Each time your foot hits the ground, your body weight plus the downward force of your weight puts pressure on your hips, legs, and feet — and on the bones in those parts of your body. This activity stimulates cells that make extra bone, thus helping to protect you against natural bone loss.
In addition to these “foot-striking” aerobic exercises, using free weights or machines that utilize resistance can help you place similar pressure on bones in other parts of your body, such as your wrists, arms, and shoulders. The result is greater bone mass — and greater protection.
Note: When this type of exercise is combined with adequate calcium supplementation, 1,000 IUs of vitamin D, and at least 400 mg of magnesium daily, the bone buildup tends to proceed more efficiently.
A 2004 study done by researchers at the National Aeronautics and Space Administration confirmed these principles rather clearly. Twenty men and women in the NASA community were divided into an exercise group and a non-exercise group for 22 weeks. All were assigned to 17 weeks of bed rest, but the exercise group did upper and lower-body exercises six days a week while the non-exercise group just rested. At the end of the study period, the resting “control” patients showed statistically significant decreases in bone-mineral density in all regions of their body except at the upper thigh (femoral neck), the outer forearm (radius), and the arms. The calcium balance in their bodies also decreased. The exercisers, in contrast, had significantly more “bone-formation markers” and calcium.
Reviewers in The Physician and Sportsmedicine journal concluded from this study that exercise may enhance calcium absorption. They also suggested that an adequate intake of calcium may be required to reap the full bone-stimulating benefits of weight-bearing exercise.
1. L.C. Shackelford; A.D. LeBlanc; T.B. Driscoll; H.J. Evans; N.J. Rianon; S.M. Smith; E. Spector; D.L. Feeback; and D. Lai. 2004. “Resistance Exercise is a Countermeasure to Disuse-Induced Bone Loss.” Journal of Applied Physiology, 97(1): 119-129. Reported in The Physician and Sportsmedicine, 2005, 33:8-9.
This excerpt comes from Start Strong, Finish Strong by Dr. Kenneth Cooper and Dr. Tyler Cooper published in 2007 (Avery). http://www.coopercomplete.com/store/detail/222.php
kmking - on March 18, 2008
That is great information. I've always been concerned about joint and ligament strain from running. I sometimes forget there is a huge benefit to bone structure as a result of the resistance. I guess balance is the key, as usual. Again, thanks for the article!fitgal2008 - on March 29, 2008
Thanks to my new connection Kim-I had not read this article previously and found it very useful and easy to read.