Osteoporosis is a thinning of the bones that occurs over time for most people. Although, most common in women, it can also affect men as they age. Osteoporosis is associated with 1.2 million bone fractures each year.

See Video: What is Osteoporosis?

Causes of Osteoporosis
One cause of osteoporosis is a lack of calcium in the diet. Adults need 1200 to 1,500 mg per day (4-5 8-ounce glasses of low-fat milk), but the average diet contains about 750 mg. For this reason, many doctors advise taking a 600 to 800 mg supplement of calcium every day, along with adequate Vitamin D intake with food or with supplements. Studies have shown this type of supplementation reduces the occurrence of hip fractures by up to 30 percent. Without enough calcium in the diet, the body will leach it from the bones, causing them to weaken over time. Without enough Vitamin D, the bones can not absorb the calcium.

Risk Factors For Osteoporosis

There are certain characteristics that increase the chances of developing osteoporosis. Among them a diet that is low in calcium and vitamin D and a lack of weight bearing exercise are three of the easiest to change. Other factors include:

   1. lower body weight (<132 pounds)
   2. rheumatoid arthritis
   3. anorexia nervosa
   4. advanced age
   5. female gender
   6. family history of osteoporosis
   7. thin or small frame
   8. early menopause or amenorrhea
   9. use of corticosteroid medications
  10. use of anticonvulsant drugs
  11. diet low in calcium
  12. lack of exercise
  13. cigarette smoking
  14. excessive use of alcohol of caffeine

The Female Athlete Triad

Another factor in the loss of bone mass is something called the female athlete triad, a combination of:

          * Low energy availability (eating disorders)
          * menstrual irregularities (amenorrhea)
          * Weak bones (increased risk of stress fractures and osteoporosis)

An attempt to reduce body fat by extreme measures not only leads to decreased exercise performance, but can lead to severe health complications. Nutrient deficiencies and fluid/electrolyte imbalance from low food intake can lead to increased risk of fractures, illness, loss of reproductive function and serious medical conditions such as dehydration, and starvation. The medical complications of this triad involve almost every body function and include the cardiovascular, endocrine, reproductive, skeletal, gastrointestinal, renal, and central nervous systems.

Also see: The American College of Sports Medicine Position Stand on the Female Athlete Triad

Many athletes mistakenly think they're not at risk for osteoporosis because they exercise and exercise is known to strengthen bones. However, research shows that exercise alone does not prevent bone loss. Irreversible bone loss starts within six months to two years of the loss of menses. Another negative consequence of eating disorders is the close association with depression.

Preventing Osteoporosis
Building and maintaining bone mass requires a combination of nutrients and exercise. Building bone density early in life is the best way to prevent osteoporosis later. After adulthood, the best way to maintain the bone mass is the same way you build it -- getting adequate calcium in your diet and doing weight bearing exercise.

Evidence shows that exercise may help build and maintain bone density at any age. Studies have seen bone density increase by doing regular resistance exercises, such as lifting weights, two or three times a week. This type of weight bearing exercise appears to stimulate bone formation, and the retention of calcium, in the bones that are bearing the load. The force of muscles pulling against bones stimulates this bone building process. So any exercise that places force on a bone will strengthen that bone.

Weight-bearing exercises are the most effective to build bones. These include activities such as walking, stair climbing, running, hiking, and weight lifting. Swimming and bicycling are not considered weight-bearing exercises.

A survey of 350 middle-aged women found that those who were most active in their daily lives had significantly greater bone density in their spines, femurs and forearms than less active women. Another study from found that running strengthens the leg bones of both older and younger women.

Exercise also increases muscle strength, coordination, and balance and decreases the likelihood of falls in the elderly.