So you've had a bone density test and your doctor has told you that you have the bones of a 75-year-old and you are only 44. Now what? Did your doctor mention exercise? Did he or she use the term weight bearing? Is that the same as weight training? The terms are sometimes confusing.

Osteoporosis is defined as reduced density of the bones. Osteopenia is a metabolic bone disease common to preterm infants but has been found in some very small boned adults. According to the National Osteoporosis Foundation, ten million Americans already have this disease and 18 million others have bone density low enough to increase their risk of osteoporosis.

What are the symptoms of osteoporosis and why is it that so many don't realize they have the problem until diagnosis? First, the disease has no symptoms unless collapsed vertebrae cause back pain, loss of height, or stooping. Only a bone density test can detect bone loss. Women seem to be at greatest risk, and can lose up to 20 percent of bone mass during the first five to seven years after menopause. This comes from the hormonal change that goes on in the body. Adding hormones at this time has been shown to prevent bone loss.

Osteoporosis in the elderly population is very common. Hip fractures are an every day occurrence. A patient that could walk before the fracture usually ends up in a long-term care facility and more often than not never regains independence.

The good news is that osteoporosis can be prevented. "Consuming adequate calcium and vitamin D lowers fracture rates in older people " says Bess Dawson-Hughes of the Jean Mayer U.S. Department of Agriculture Human Nutrition Research Center on Aging at Tufts University in Boston.

Dawson-Hughes adds that exercise has the greatest effect when women consume more than 1000 mg of calcium a day from food and supplements. It is recommended that you get your vitamins from your food first -- then supplement, if needed.

Weight bearing exercises are those that are done in a full upright (standing) position. These exercises can strengthen bones. Weight bearing exercises include walking, jogging, dancing, snowshoeing, skiing, etc. Swimming, bicycling, and rowing are excellent cardiovascular exercises, though they do nothing for bone health.

Strength (weight) training exercises are very important. Simply lifting light hand weights in muscle endurance exercises will increase lean body mass, putting more weight on bones, thus making them stronger. The combination of weight bearing exercises (walking, jogging, dancing, skiing, etc.) and strength training exercises (lifting weights or using weight machines) are the best ways to not only retard osteoporosis but prevent it.

Eating a lot of green leafy vegetables will ensure you are getting some of the calcium that you require on a daily basis. Drinking milk, eating yogurt and cheese (if you are trying to lose weight, opt for the low-fat or non-fat versions) are also very beneficial to bone health. The combination of eating right and exercising daily will keep you healthy and fit.

Smoking has been determined to be a leading factor in the cause of osteoporosis. It is said to leach calcium out of your bones, making them lacy and breakable. We all have heard and know that smoking cigarettes are bad for our health: here is just one more reason to do the right thing and quit. If you are serious about ridding your body of nicotine, talk to your health care provider and s/he will be able to recommend things that can help you stop smoking for good.

It has been said that exercise is the remedy for just about every disease.

Strength training has been recognized as the closest thing to the "Fountain of Youth" that we have in today's modern society. So get out there and start walking! Most malls have walking programs for those of us who don't want to face the elements of winter. There are also various fitness clubs that have walking facilities. The Anchorage Senior Center has a great weight room and wonderful fitness classes.

One word of caution, however: always check with your doctor before you start an exercise program. If you have any leg pain that begins with walking and stops with rest, please see your doctor; just as chest pain requires medical attention so does this type of leg pain.

It has been documented that regular exercise lowers blood pressure and cholesterol, helps control some diabetes, and reduces the risk of heart disease, stroke and some cancers. Exercise also boosts self-esteem and helps controls weight. Another benefit that we receive from regular exercise is flexibility, balance, and mental sharpness. In all my reading and research I have yet to discover anything negative about exercising.

The latest data shows that moderate exercise gives health benefits, so you don't have to run a marathon to feel healthier. Plan to walk a little each day to improve your overall health. Then progress yourself so you stay challenged. Remember: exercise might not add years to your life, but it does add life to your years.

Bonnie Murphy specializes in exercise with mature women. She is the owner of BFIT Consulting and is the Fitness Manager at the Anchorage Senior Center. Call 276-BFIT for more information.