SWIMMING AND OSTEOPOROSIS
Osteoporosis is a subject, which should be near and dear to the hearts of most masters swimmers, but which many choose to ignore. Many swimmers think it won't affect them, either because they feel fine, or because they exercise. They are only partially right, and what they don't know can hurt them.
Osteoporosis is a disorder that affects the entire skeleton. It is characterized by a significant loss of bone mass leading to an increased susceptibility to fractures of the hip, spine, and wrist. It affects up to 24 million Americans, of which 80% are women. It is estimated that currently 10 million individuals already have osteoporosis, with 14 million more having low bone density (osteopenia). That means that approximately 1 in 4 women and 1 in 8 men over the age of 50 have osteoporosis.
As it is a painless condition, most people are unaware they have osteoporosis. Often the first sign of significant bone loss is a fracture, usually of the hip, forearm, or vertebra. About 32% of women and 17% of men in the United States who live until age 80 experience a hip fracture. The risk of vertebral fractures is even higher. Hip fractures in the elderly are far more than an inconvenience—1 in 4 patients over the age of 50 dies within the year following a hip fracture.
Although some cases of osteoporosis are due to drugs (i.e., steroids) or the result of a disease (i.e., rheumatoid arthritis), most cases are due to either older age (senile osteoporosis), or to a drop in estrogen (postmenopausal osteoporosis). If one of your parents had a hip, forearm, or vertebral fracture you can pretty much assume that you are at risk for osteoporosis. However, the converse is not necessarily true.
Bones are constantly remodeling. While in space, astronauts' bodies respond to the lack of gravitational stress on the bones by decreasing their bone mass. On the other end of the spectrum, weightlifters experience an increase in bone density due to the stress of the extra weight on the bones. The more stress placed on the bones over a period of time, either through heavy weights and/or by impact, the more the body responds by increasing the bone density.
The process is actually a bit more complex than that. Not only does the body lay down more bone, it actually remodels the structure of the bone along the lines of stress. If you take up running, eventually your body will remodel the structure within the bones in response to the new stress. Stress fractures are often caused by running too much, before the body has had a chance to remodel the bones based on the new stresses.
So where does swimming fit in? Unfortunately swimming does not place any significant stress on the bones. Study after study comparing swimmers with other athletes, shows swimmers to have similar bone density to couch potatoes. Even the increase in muscle mass, and the concomitant pull on the bones, is not enough to stimulate a significant increase in bone density. This is not to say that older people shouldn't swim. Of course swimming is wonderful for cardiovascular fitness, flexibility, and a certain amount of strength. Swimming with a masters team has the added advantage of a social environment, shown to be a significant factor in health and longevity.
What is a swimmer to do?
Swimmers need to supplement their aquatics training with some weight-bearing exercise. The optimal sports for maintaining or increasing bone density, as well as improving overall coordination, are weightlifting, basketball, and volleyball. Running, jumping rope, and hiking, are not quite as effective at building bone, but will help improve coordination. Yoga does not increase bone density. However, it is an excellent way to improve strength, flexibility, and coordination, which are all important in preventing falls.
What about diet?
In addition to eating a well-balanced diet, rich in fruits and vegetables, most older adults need to supplement their diet with extra calcium (usually combined with magnesium in a 2:1 ratio). The most absorbable forms of calcium are calcium citrate, gluconate, or lactate. Calcium carbonate and oyster shell are less effective. Most people should get between 800 and 1000 mg of calcium per day, while postmenopausal women should increase to 1500 mg per day. Soy products also help stimulate bone production.
Is there more?
There is a painless test, which measures bone density. This and other topics, such as the various diagnostic and monitoring methods, supplemental hormones, drug therapies, and micro-nutrients are important but beyond the scope of this article. Let me know if you are interested in more information.
Jessica Seaton, D.C. is a chiropractic orthopedist in private practice in West Los Angeles. She is chairperson of the SPMA Sports Medicine Committee and a member of the USMS Sports Medicine Committee. She has been swimming with West Hollywood Aquatics for over ten years. She can be reached at (310) 470-0282 or Jseaton@aol.com.