Are you doing the right workout? How you exercise has a significant impact on your weight, metabolism, body fat and strength. Take our quiz to see if you're making the best choices - Health Quiz

Shape, July, 2002 by Suzanne Schlosberg

When you watch an older woman shuffle down the street or accept help carrying groceries, you probably think you've witnessed a normal part of aging. Sure, that day may be decades away for you, but we're all destined to slow down eventually, right? Not necessarily. Scientists are discovering that much of what we consider aging -- the loss of strength, stamina, bone density, balance and flexibility -- is actually due to inactivity. "Sure, your hair is going to turn gray, and you may not be able to do a back handspring when you're 70, but if you stay fit, you can still ride a bike or go skiing," says Rebecca Seguin, B.S., project manager at the Center for Physical Activity & Nutrition at Tufts University in Boston. You'll have the strength to carry your skis to the slopes and the bone density to fall without breaking your hip.

"We don't know how to extend life, but we do know what it takes to live a high-quality life," says Kent Adams, Ph.D., an exercise physiologist at the University of Louisville in Kentucky, who has reviewed more than 80 studies on aging and exercise. What it takes, of course, is exercise. But what kind? As researchers are learning, not just any workout program will keep you lean, lithe and vital into your later years. The workouts you do today will impact your weight, health, fitness and well-being for decades to come. Take this quiz and find out whether your assumptions about exercise and aging are correct. (Then see "Fitter, Firmer & Younger," page 172, for the right workout for your age group.),

1. Starting in their mid-30s, women tend to lose about 1/3-1/2 pound of muscle each year while gaining 1/3 pound of fat. How much of this can be prevented with exercise?

a) None of the muscle loss but all of the fat gain

b) 50 percent of the muscle loss and nearly 50 percent of the fat gain

c) 75 percent of the muscle loss and 25 percent of the fat gain

d) All of the muscle loss and all of the fat gain

Answer: d. You can prevent all of the muscle loss and fat gain that occur in premenopausal women, as long as your exercise program includes strength training twice a week with heavy enough weights to fatigue your muscles between eight to 12 repetitions. Jogging or swimming can help stave off fat gain but is not sufficient for maintaining muscle mass. In a study published in the International Journal of Sports Medicine, very experienced swimmers and runners around age 70 were found to have about the same amount of muscle mass as sedentary people their age. However, 70-year-olds who had lifted weights regularly for more than a decade had as much muscle as 28-year-olds. After menopause, some muscle loss and fat gain may be inevitable due to hormonal changes, but experts believe strength training can keep those changes to a minimum.

2. By age 75, what percentage of women in the United States can't lift objects heavier than 10 pounds?

a) 22 percent

b) 35 percent

c) 52 percent

d) 66 percent

Answer: d. A whopping two-thirds of all women age 75 and older can't even lift a grocery bag containing a gallon of milk and a few cans of soup. Of men age 75 and older, 28 percent can't make the lift. On average, from age 30 to age 70, men and women lose 30-40 percent of their strength. Though we don't know precisely how much strength can be retained, research shows that people who lift weights regularly can maintain a very high level of strength throughout their lives. And people who start lifting weights in middle age can become stronger than they ever were.

3. The resting metabolic rate of a 20-year-old woman who is 5-foot-4 and weighs 140 pounds is about 1,478 calories per day. If this woman does not lift weights, her metabolism will slow down. By age 50, about how many calories will she burn each day?

a) 1,410

b) 1,337

c) 1,225

d) 1,005

Answer: c. She'll burn about 1,225 calories per day -- a drop of 253 calories (because she would lose about 6 pounds of muscle and gain about 5 pounds of fat starting at age 35). Among postmenopausal sedentary women, just 16 weeks of strength training can lead to gains of 10-15 percent in resting metabolic rate, research shows.

4. From age 35 until menopause (average age: 51), women lose on average 1 percent of their bone mass each year. How much of this bone loss is inevitable?

a) None

b) 10-12 percent

c) 20 percent

d) 30-35 percent

Answer: a. There's no reason premenopausal women need to lose bone. Even after menopause, most, if not all, bone loss can be prevented through strength training and healthy eating, and some lost bone can be regained. In a study of 50- to 70-year-old women (none of whom were taking estrogen) published in the Journal of the American Medical Association, subjects who lifted weights twice a week for one year increased bone density by 1 percent; those who didn't lift weights lost 2 percent. Even if you lose some bone mass after menopause, banking away enough bone when you're young will ensure that you have sufficient reserves later in life to avoid osteoporosis.

5. Which of these exercise regimens -- along with sufficient calcium and vitamin-D intake -- will suffice to preserve bone density up to menopause?