Like it or not, every one of us is getting older, day by day. The following information in this article can help you chart a healthy course into your future to help retain a youthful fitness level.
Aerobic capacity declines as we age as proven by The Baltimore Longitudinal Study on Aging. The average person loses about 1% of their fitness per year. Aerobic capacity decline begins to be noticeable as we enter our 40-plus years and declines more rapid, particularly after age 60. Individuals who stay active and maintain a higher ability to uptake oxygen throughout life maintain a greater fitness level at all points in the aging spectrum than their sedentary counterparts.
Muscle is an active tissue. It contributes about 20 percent of the body’s Resting Metabolic Rate. Science estimates the metabolic rate of muscle is about 10 to 15 kcal/kg per day, which is approximately 4.5 to 7.0 kcal/lb. per day. Muscle tissue contributes approximately 20% to Total Daily Energy Expenditure versus 5% for fat tissue (for individuals with about 20% body fat). Resistance training studies, lasting from 8 to 52 weeks show increases of 2.2 to 4.5 lbs of muscle mass. Therefore, the 4.5 lbs of muscle mass would increase the resting metabolic rate by about 50 kilocalories per day. That does not sound like much but it adds up over time. It is simple, the more muscle you have, the more calories you will burn, thus, 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. Loss of muscle mass, also known as Sarcopenia, occurs as a result of aging. After age 35 you will lose between .5-1 lb. of muscle. Studies have shown a person loses 50% of lean mass from age 20 to 90, with those age 50 to 70 losing 30% of their muscle strength! By engaging in regular resistance training and following a sound diet that includes adequate amounts of protein, you can prevent most of the muscle loss associated with age.
We’re all born with a fixed percentage of slow-twitch and fast-twitch muscle fibers. Across a broad population, muscle composition is forty percent to fifty percent Type I, and fifty percent to sixty percent Type II. Our physical activities determine what happens, including increasing muscle mass and strength by engaging in an activity, or losing mass and strength due to inactivity.
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 if we do not use them. For example, we need fast-twitch muscle fibers for golf, tennis accelerating, getting up from the floor and climbing up stairs. 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.
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. A study with obese people suggests they sat three hours more per day than their lean peers; this saved them about 350 calories a day.
Body fat secretes adipokines (hormones) that have negative effects on muscle strength and contribute to increased inflammation, particularly after age 60 to 70. Inflammation leads to heart disease and diabetes.
When young people gain weight, about one-third of the weight gained is lean muscle. When older people gain weight it is all fat. When older people lose weight (due to illness or a low-calorie diet), half of the weight lost is muscle. Yo-Yo dieters who gain fat and lose muscle are on a downward spiral. Being fat but fit is preferable to going on and off diets.
Muscle loss is the key reason why older people become frail and end up in nursing homes. When they stop exercising, they experience a steep drop in strength. The good news is they can do something about frailty: lift weights! In only 12 weeks, 60– to 70-year old men regained the fitness they had lost over 15 years. Even 90-year-olds in a nursing home can triple their strength in 10 weeks.
How much weight should people lift to build muscle? A very general recommendation is to perform three sets; the first two sets should have 8 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. Muscle damage stimulates muscle growth so you want to spend more time lowering the weight than lifting it.
Most strength gains occur in the first 3 months of starting a lifting program, due to early neuromuscular changes. The nervous system learns how to recruit muscles more efficiently. This stimulates more muscle cells.
Strength training helps prevent bone loss. In a year-long study with post-menopausal women, all of the women who lifted weight improved their bone health. Those who did not lift weights lost approximately 2 percent bone density in one year. Exercise is better than osteoporosis drugs, broken bones to prevent bone loss, plus you will get stronger.
By lifting weights and building muscle, older people should be able to eat more calories which can boost their intake of health-promoting protein, vitamins and minerals.
If you don’t intentionally rebuild muscle through exercise, you’ll need to eat 150 to 450 fewer calories every day every 10 years to maintain your current weight.
So if you’re at a stable weight at age 35 and didn’t do any kind of resistance training, while still eating the same amount of food, you’ll gain weight. Adding exercise does not always entitle a person to eat more calories. One study showed that those who walked briskly for an hour a day (five days/week) for 3 months, their daily energy expenditure remained stable-despite the brisk walking. This is due to becoming more sedentary the rest of the day.
About 25-33 percent of people older than 65 years are eating too little protein. This results in loss of muscle and bone, and leads to medical problems. The goal is to eat at least .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. A good example is for breakfast: 3 eggs; lunch: 1 can of tuna; dinner: 4 oz. chicken.
Stay young by staying active and by lifting weights or doing some type of resistance exercise to strengthen both muscles and bones. Review your program with your fitness coach to ensure the results you are looking for. Use it or lose it!