The Link Between Exercise and Healthy Bones

Weight-bearing exercises reduce osteoporosis risk

Exercise is known to increase bone density and improve overall bone health. However, not all exercises are equal when it comes to building strong bones or preventing osteoporosis (bone mineral loss). This is not only true for casual gymgoers but elite athletes as well.

Factors for Bone Growth

Researchers from the University of Michigan reviewed data as far back as 1961 to determine what impact exercise has on bone density. In their research, the investigators found three characteristics of exercise have the largest impact on bone mass density (BMD):

  • The magnitude of muscle strain an exercise exerts. Exercises that fit into this category include weightlifting and gymnastics because the amount of force placed on muscles and bones.
  • The rate of muscle strain an exercise exerts. This indicates the speed by which repetitive, high-impact exercises, such as tennis or plyometrics, are performed.
  • The frequency by which muscle strains occurs. Running is a prime example of this as the impact on muscles is not only repetitive but continues for a long period of time.

Although the researchers did not establish which of the three factors is the most important, they concluded that increased density can be had with as little as 12 to 20 minutes of weight-bearing exercise performed thrice weekly.

Bone Health by Exercise

While it would be fair to assume that any exercise that places significant, repetitive stress on a bone would be equally beneficial, it's not always the case. According to research from Brigham Young University, one exercise arguably offers greater benefit than all others: jumping.

Jumping 10 to 20 times a day with 30 seconds of breaks in between jumps significantly improved hip bone mass density (BMD) in women age 25 to 50 after 16 weeks.

Bone density increases directly coincided with the amount of exercise performed. According to the investigators, jumping 20 times twice daily resulted in 75 percent greater BMD than doing 10 jumps twice daily.

While running also offered significant improvement in BMD, it was far less than that seen with jumping. This suggests that jumping should be incorporated into any exercise program, including low-impact activities like cycling, swimming, and running.

Exercise and Bone Loss

Not every sport or exercise activity is linked to BMD gain. The current body of evidence suggests that running is linked to greater BMD than low-impact activities like cycling because of the direct stress that it places on the legs and hips. By contrast, elite-level cyclists appear to have a greater propensity for bone loss compared to their running counterparts.

The causes of this are many. In addition to the absence of direct bone stress, some experts believe that the loss of calcium in sweat also plays a key role. It is also possible that endurance sports in and of themselves can promote bone loss as more calories tend to be burned than consumed.

What this suggests is that greater effort may be needed to incorporate weight training into the training schedules of endurance athletes.

Best Exercises for Bone Density

The benefits of exercise can be felt at any age and with as little as two to three days of exercise per week. Even in older women for whom jumping and running may be inappropriate, resistance training can help stimulate or maintain BMD in the weight-bearing bones.

With resistance training, the force of muscle pulling against bone appears to be enough to stimulate bone growth even if the actual stress placed on the bone is moderate. The range of exercises linked to increased BMD include:

Nutrition and Bone Health

Building or maintaining bone mass requires more than weight-bearing exercise; good nutrition is also key. Once you reach the age of 30, you don't build bone as readily as you used to. To maintain strong bones, you need to ensure the proper intake of calcium and vitamin D in your diet. This is especially true if you are at risk of osteoporosis.

Calcium is the key building block for bones. Vitamin D helps the body absorb calcium. To sustain bone health, adults should get 1,000 milligrams (mg) of calcium per day and 600 international units (IU) of vitamin D per day, ideally from food sources.

Women over 50 and men over 70 should increase their daily calcium intake to 1,200 mg. After 70, men and women should get no less than 800 IU of vitamin D daily. Some osteoporosis experts even recommend 800 to 1,200 IU of vitamin D per day.

The best food sources of calcium and vitamin D include:

  • Dairy products, including milk, yogurt, and cheese
  • Leafy vegetables such as kale, broccoli, and spinach
  • Seafood such as oysters, crab, and shrimp
  • Fishes such as salmon, tuna, and sardines
  • Calcium-fortified soy and almond milk

If you are unable to meet your daily intake needs, speak with your doctor about calcium supplements in tablet form, including calcium citrate and calcium carbonate.

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