Live Healthy Live Well

You know that you shed skin cells every day. About 30,000-40,000 of them fall off every hour. Over the course of a day, you shed over a million skin cells. Actually, most of the dust you see in your house is former parts of yourself. Eeuwww!! But what you might not realize because (a) no one ever told you, and (b) you can’t see through your skin, is that bone cells also die every day. Bone cells are living cells just like your skin cells; they eventually grow old and die. But unlike skin cells that fall off and land on the coffee table, old bone cells are reabsorbed and used to create new bone tissue.

Inside your bones you have two “teams” of cells; one team’s cells (osteoblasts) lay down new bone. The other team’s cells (osteoclasts) chew up old bone. Ideally, you want the team that makes new bone to outweigh the team that takes away old bone, and for most of our childhood and young adulthood, that is exactly what happens. But as we age, the bone cell destroyers start to outnumber the bone builders. That’s when we begin to develop osteoporosis.This makes bones weak and porous, which raises the risk for fractures. Fortunately, there are many strategies you can employ to keep your bones hard and strong. Getting enough calcium and Vitamin D in your diet is one method, but being physically active is another.

So how does exercise help prevent osteoporosis? Moving your body enables you to build and maintain the amount (bone mass) and thickness (density) of your bones. When your body is moving, muscles pull against the bone. The stress causes minerals (mainly calcium) to be deposited in the bone. This makes the bone stronger and denser.

You need three different types of exercise to help lower your risk for getting osteoporosis: weight-bearing, resistance, and flexibility.

The first (and best) type of exercise to protect against osteoporosis is weight-bearing exercise. Weight-bearing means your feet and legs are supporting your body’s weight. Examples of weight-bearing exercise include walking, going up and down the stairs, and housework. However, weight-bearing exercise primarily affects bones below the waist, so you need other sources of activity to challenge the upper half of your body. Playing tennis and mowing the lawn are examples of activities that benefit the whole body.

Resistance exercise uses an object to create challenge or “friction.” When you’re working against the weight of an item such as free weights, weight machines, or resistance bands and tubing, you strengthen the muscles surrounding your bones and increase bone density.

And lastly, flexibility is important because your body needs to be able to bend and flow. Stretching, Tai chi, and yoga all promote balance and strength. These types of exercise will not slow down the loss of bone, but may decrease the risk of falls and fractures. When you twist, bend, and stretch, you strengthen the sites most at risk; primarily where your upper arm meets your shoulder, where your forearm meets your wrist, where your thigh bone meets your hip, and your spine.

Sources:
http://www.nof.org/articles/238
http://www.webmd.com/osteoporosis/guide/osteoporosis-exercise
http://wiki.answers.com/Q/What_is_the_effect_of_exercise_on_the_bones_and_joints
http://www.acefitness.org

Written by:

Donna Green
Educator, Family and Consumer Sciences
Ohio State University Extension

Reviewed by:

Elizabeth Smith, MS, RD, LD
Educator, Family and Consumer Sciences
Ohio State University Extension