Exercise and bone health

The defining feature of osteoporosis is loss of bone density and deterioration in bone quality, which causes bones to become weaker and more likely to fracture. One of the ways to promote bone health and strength is through physical exercise.

“There are a lot of studies that show that good physical activity helps prevent bone loss and also helps prevent falls, and we know that prevention of falls leads to a decrease in osteoporotic fractures,” says Dr. Sandra Kim, medical director of the Centre for Osteoporosis and Bone Health at Women’s College Hospital.

Dr. Kim explains that several types of exercise and fitness elements are important in bone health and fall prevention. These include not only weight-bearing exercise, but also muscle-strengthening exercise, activities that improve balance, and posture training.

“I often tell my patients to think of bone as dynamic tissue. A lot of people think of bone as static tissue, but it’s living tissue just like your skin,” Dr. Kim says. “I like to use the analogy of your bones to your skin: that the bones are constantly going through a remodelling cycle where old bone tissue is being sloughed off and new bone tissue is being formed for repair and renewal, just like your skin does.”

Just as skin repairs itself when there is a cut or scrape, bones do the same thing on a slower cycle. Exercise encourages this process of healthy bone remodelling and helps preserve the musculoskeletal system. Bone quantity and quality is enhanced by exercise and compromised by inactivity and advancing age.  “Day to day there’s going to be wear and tear on your bones, little micro-cracks that need to be repaired with renewed bone tissue,” Dr. Kim says. “Exercises that work on muscle strengthening combined with weight-bearing activities, help stimulate bone growth and slow the rate of bone loss as we age.”

Weight-bearing exercise, strength and balance

Osteoporosis Canada recommends doing weight-bearing aerobic activities such as running, jogging, climbing stairs, dancing or walking most days of the week, for 20 to 30 minutes. The goal is a total of 150 minutes of moderate to vigorous activity per week.

However, Dr. Kim cautions that other components of fitness are also important to bone health and in preventing falls.

“That message about weight-bearing exercises and walking is important, but we know that that in itself is not enough,” she says. “You need to incorporate exercises that also work on muscle strengthening at least twice a week. Also exercises that challenge your balance, and examples of that would include things like Tai Chi. Physical activities that work on back extensor muscles and good posture are also important.”

Osteoporosis Canada recommends twice-a-week strength training of major muscle groups in addition to doing balance activities every day. Posture awareness and using safe movements on a daily basis are also recommended.

“It’s very important how you do your daily activities when it comes to bending and picking things up and twisting motions,” Dr. Kim explains. “One of the most common osteoporotic fractures are spine fractures. The majority of those fractures actually occur spontaneously from spine loading and are silent, meaning that people don’t even experience pain and they may only experience height loss over time or develop a hunched posture.”