Ageing and Cycling

Aging and Cycling

By Alan Bragman D.C.

eaching 40 may not be too traumatic from a performance standpoint, but 50 is a different matter. You're long past the age when even the oldest pros compete, and you start taking a keen interest in Viagra and Cialis ads. At 50 it's time to face up to the fact that you need to figure out ways to keep from getting dropped by riders half your age.

What are the changes that occur in our bodies as we age? The average body is at its peak in the late 20s when we are at a phase known as homeostasis, the point where the number of cells dying and the number of cells being produced are roughly equal. After this time the number of dying cells surpasses the body’s ability to produce new ones. Let’s look at how this change affects various aspects of overall health and athletic performance.

First, the Bad News

Cardiovascular System. As we age our VO₂ max declines. This is the ability to deliver oxygen to muscles and other areas of the body. This decline begins around age 20 due to a decrease in maximum heart rate and stroke volume (the amount of blood the heart pumps with each beat). Max heart rate drops by 0.6 beats per minute every year or 6 beats per decade in individuals active in endurance activities. In sedentary people the decrease is twice as fast. Meanwhile, stroke volume decreases about 1/3 percent per year, or a little over 3% per decade.

In addition, as we age the number of capillaries (the place where oxygen exchange occurs) declines. Aging causes lungs to become less elastic. The chest wall and diaphragm weaken and lose flexibility. These changes cause increased airway resistance as we breathe. The maximum expiratory ventilation (volume of air you can breathe in a minute) also begins to decline in the late 20s or early 30s. It's down to half by the time we reach age 60.

As our circulatory system ages we build up fatty plaque deposits along the walls of blood vessels, a condition known as arteriosclerosis or arthrosclerosis. Over time these deposits harden and thicken. They may eventually interfere with blood flow, circulation and the elasticity of the vessels.

To view the rest of the article, please click here: Ageing_Cycling (PDF, 115 KB).