Like it or not, everyone gets older, day by day. As a regular fitness exerciser or athlete, you might wonder how aging impacts your performance, and what you can do to retain your youthful vigor. The following information can help you chart a healthy course into a long and healthy future.
Preventing Muscle and Bone Loss
Becomes a Priority with Age
The average person loses about one percent of his or her physical fitness per year. Aerobic capacity goes down, particularly after age 60. Staying active helps maintain a slightly higher ability to uptake oxygen compared to being sedentary, but the rate of loss is the same.
Muscle is an active tissue. The more muscle you have, the more calories you can eat without getting fat. Muscle loss creates a subtle change in metabolism that can contribute to weight gain with aging.
We lose muscle as we age, starting as young as age 20, with a steady decline year after year. To treat this age-related loss of muscle mass, you need to lift weights or do other forms of resistance exercise. Yet, even strong athletes still lose muscle as they grow older.
With aging, we lose 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. By contrast, elite distance runners can maintain their slow-twitch muscle fibers into their 40s. But even top athletes notice a slowdown after 40 because the nerves connecting 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.
Most people not only lose muscle as they get older but also tend to gain fat. It’s easy to eat more, even though the aging body needs less food. But the cause of weight gain is not a “slow metabolism.” Metabolic rate remains constant, but daily activity typically declines. A study of obese people suggests they sit three hours more per day compared to their leaner peers, resulting in less energy expenditure of about 350 calories a day.
Body fat secretes adipokines (hormones) that have negative effects on muscle strength and contributes to increased inflammation, particularly after the age of 60. Inflammation can be a precursor to heart disease and diabetes. Hence, excessive body fat can be a predictor of disability in people ages 50 to 75. So, it’s best to stay lean!
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 all fat. However, when an older person loses weight, due to illness or a low-calorie diet, half of the weight lost is muscle. So-called “yoyo dieters” who gain fat but lose muscle can quickly embark on a downward spiral. That’s why being fat but fit is preferable to going on and off diets.
Also, muscle loss is a key reason why older people become frail and end up in nursing homes. When they stop exercising, they experience a steep drop in physical strength. The good news is that something can be done about frailty: lift weights! In a12 weeks study, 60- to 70-year-old men regained the fitness they had lost over 15 years prior.
To maintain (but not gain) strength, a person can lift weights just one day a week. Weight lifting does not stress the heart or increase blood pressure. Aerobic exercise actually causes a greater spike in blood pressure because it uses more muscles and more oxygen, which means the heart has to pump more blood than with strength training.
Even 90-year-olds have shown the ability to triple their strength in just weeks. That means they can walk better and stay independent. So tell your parents and grandparents to start a strength training program, so they can stay out of the nursing home!
How much weight should most people lift to build muscle? Three sets. The first two sets should have eight reps; the final set is to exhaustion. If you can lift a weight 12 times in the final set, you need to lift heavier weights the next time. Because muscle damage stimulates muscles growth, you want to spend more time lowering the weight than lifting it.
Most strength gains occur in the first three months of starting a weight lifting program, due to early neuro-muscular changes. The nervous system learns how to recruit muscles more efficiently, and this stimulates more muscle cells.
Strength training also helps prevent bone loss. In a year-long study with post-menopausal women, all of the women who lifted weights improved their bone health. Those who did not lift weights lost ~2 percent bone density in just one year. Besides, exercise is better than using anti-osteoporosis drugs. Plus, you’ll get stronger!
By lifting weights and building muscle, older people should be able to eat more calories, which boosts their intake of health-promoting protein, vitamins, minerals. Yet, adding exercise does not automatically entitle a person to consume more food. In a study with 62-year-olds who walked briskly for one hour a day, five days a week, for 3 months, the daily energy expenditure remained stable, despite the brisk walking. How could that be? As it turned out, they became more sedentary the rest of the day, napped more, and slept longer. In other words, they compensated for having exercised.
About 25- to 33-percent of people older than 65 years don’t eat enough protein. This results in muscle and bone loss and possibly expensive medical problems. The goal is to eat at least 0.55 grams of protein per pound of body weight each day to maintain and build muscle. For a 140-pound person, this equates to about 75 grams of protein, or 25 grams per meal – for example, Breakfast: 3 eggs; Lunch: 1 can tuna; Dinner: 4 oz. chicken.
The bottom line is this: Stay young by staying active and by lifting weights or doing some type of resistance exercise to strengthen both muscles and bones. And remember the words of the famous gerontologist Water Bortz: “No one really lives long enough to die of old age. We die from accidents and most of all, from disuse.” So use it or lose it!
Nancy Clark, MS, RD, CSSD (Board Certified Specialist in Sports Dietetics) counsels both casual and competitive athletes at her office in Newton, MA (Ph: 617-795-1875). Her Sports Nutrition Guidebook and food guides for new runners, marathoners, and soccer players offer additional information. For more information, please visit www.nancyclarkrd.com and www.NutritionSportsExerciseCEUs.com.
The information presented in this article originated from a workshop by Dr. William Evans, an exercise physiologist and expert on aging, muscle maintenance, and protein.
The articles written by guest contributors are the sole responsibility of the individual writers in terms of factual accuracy and opinion and do not necessarily reflect the views of the publisher of this blog.