Like it or not, each one of us is getting older every day. As a runner, you might wonder how aging impacts performance and what you can do to retain youthful fitness.
In a recent workshop, Dr. William Evans, an exercise physiologist and expert on aging, muscles and protein, recommended the following tips to help you chart a healthy course into your future:
1. The average person loses about 1 percent of their fitness per year. Aerobic capacity goes down, particularly after age 60. Staying active helps maintain a slightly higher ability to uptake oxygen than a non-athlete, but the rate of loss is the same.
2. Muscle is an active tissue. The more muscle you have, the more calories you can eat without getting fat. Yet, muscle loss creates a subtle change in metabolism that can contribute to weight gain with aging.
3. We lose muscle as we age, starting as young as age 20, with a steady decline year after year. To counter the loss of muscle, lift weights or do other forms of resistance exercise. Yet, even strong athletes still lose some muscle with aging.
4. With aging, the average person loses more fast-twitch muscle fibers (used in sprinting) than slow-twitch fibers (used for endurance). This loss starts early in life and explains why elite sprinters peak in their early 20s. In comparison, elite distance runners maintain their slow-twitch muscle fibers until age 40. But even top athletes notice they slow down after age 40, at which time the nerves that connect to muscles start to die off, resulting in a loss of both slow- and fast-twitch fibers. Athletes can lose about 20 percent of their muscle fibers between ages 40 and 70.
5. With age, we not only lose muscle but also tend to gain fat. The cause of weight gain is not due to a slow metabolism. Metabolic rate remains constant, but daily activity easily declines with age. A study of obese people suggested that they sat three hours more per day than their lean peers, who also burned 350 more calories a day.
6. Body fat secretes adipokines (hormones) that have negative effects on muscle strength and contribute to increased inflammation, particularly after age 60. Inflammation leads to heart disease and diabetes. Hence, excess body fat can be a powerful predictor of disability in people ages 50 to 75.
7. When young people gain weight, about one-third of the weight gained is lean muscle. When older people, in particular older women, gain weight, it's usually fat. When older people lose weight—due to illness or a low-calorie diet—half of the weight lost is muscle.