Bone Up on Fitness

Weight-bearing exercise helps build bone density.

Exercise is important for reducing stress, maintaining a healthy weight, and promoting cardiovascular health, but it also holds the key to another, less visible, component to our health—our bones.

Our bones are a vital component of our health. Bone is living tissue that responds to exercise by growing stronger. Most of us begin to lose bone density after our third decade. Low bone density, referred to as osteopenia, can lead to osteoporosis (bone loss) and a significant risk of bone injury, including fractures.

Bone loss is a silent condition. It has no symptoms and occurs slowly over the years. Many people have no idea that they have suffered bone loss until one day, they trip, fall, and fracture a bone. We can prevent bone loss by continuing to build bone density throughout our lives.

Exercise and Bone Density

Weight-bearing exercise has been shown to increase bone density and improve bone health. Weight-bearing exercise is physical activity we perform while on our feet and legs that works the muscles and bones against gravity. During weight-bearing activity, the muscles and tendons apply tension to the bones, which stimulates the bones to produce more bone tissue. As a result, bones become stronger and more dense and the risk of osteopenia, osteoporosis, and fractures decreases.

Researchers from the Bone & Joint Injury Prevention & Rehabilitation Center at the University of Michigan have identified several characteristics of exercise that have an impact on bone density1:

  • Strain magnitude refers to the force or impact of the exercise. Exercises such as gymnastics and weightlifting have a high strain magnitude.
  • Strain rate refers to the rate of impact of the exercise. Exercises such as jumping or plyometrics have a high strain rate.
  • Strain frequency refers to the frequency of impact during the exercise session. Exercises such as running have a high strain frequency.

The magnitude, rate, and frequency of strain during exercise all play a role in building bone density.

Choosing Weight-bearing Exercise

Weight-bearing exercise can utilize your own body weight or equipment such as weights or machines. Any exercise that places force on a bone will strengthen the bone. Some examples of weight-bearing exercise include:

  • Running
  • Walking
  • Weight-lifting
  • Hiking
  • Strength training (such as push-ups, lunges, squats)
  • Tennis
  • Climbing stairs
  • Jumping rope
  • Plyometrics
  • Aerobics
  • Soccer
  • Baseball
  • Basketball
  • Volleyball
  • Gymnastics

Examples of non-weight-bearing exercise:

  • Swimming
  • Cycling

(These activities are valuable for building cardiovascular health and strength, but they do not help build bone density.)

Building Bone Health Throughout Life

Once we reach the age of 30, we typically start losing bone density, so it’s important to build bone density early on in order to prevent osteoporosis later in life. If you’re past the age of 30, don’t fret. It’s never too late to build bone health. Weight-bearing exercise is beneficial at every stage of life: childhood, adolescence, and adulthood. The University of Michigan researchers found that as little as 15-20 minutes of weight-bearing exercise, three days a week was sufficient for building bone density.

So, choose your activity and let strength and gravity go to work to help you build healthy bones for a lifetime.

Reference:


1 Manske SL, Lorincz CR, Zernicke RF. Bone Health: Part 2, Physical Activity. Sports Health: A Multidisciplinary Approach July 2009 1:341-346.