Give me strength: why you need to lift weights.

Too tired or dogged by arthritis pain to exercise? Does it jiggle where once there was muscle? Eating less but weighting more?

No. This isn't a pitch for Flab-Be-Gone. But if you've got an hour a week, you really can reverse those and other problems that creep up as you age.

Strength-building exercises build more than strength. They boost bone density, metabolic rate, balance, and self-confidence. And they trim more than flab. Strength training can curb depression, sleep problems, high blood sugar, arthritis pain, and possibly the risk of heart disease.

"Isn't it great that there's a lifestyle routine that makes you healthy and makes you look good," says exercise expert Miriam Nelson of Tufts University.

And you can do it at home for next to nothing.

Why Muscle Matters

Q: Why is strength training so important for older people?

A: Starting in their late 30s or early 40s, most people lose about a quarter pound of muscle every year. By the time they're 80, they've typically lost about a third of their muscle mass. The loss of muscle as we grow older is called sarcopenia. We don't know how much is hardwired to the aging process and how much is caused by poor nutrition and physical inactivity.

Q: Why does muscle matter?

A: Muscle is the absolute centerpiece for being healthy, vital, and independent as we grow older. It keeps us strong and mobile. It tugs on bone to help bone stay strong.

And it burns more calories than fat burns. Muscle and lean body mass are the metabolic engine in your body. So more muscle means your metabolic rate goes up, which makes it easier to stay trim.

Muscle is also where most of our blood sugar, or glucose, goes. When you eat food, glucose goes into the bloodstream and most of it gets deposited in the muscle as stored glycogen.

Q: So building more muscle means lower blood sugar?

A: Yes. We're seeing all epidemic of type 2 diabetes because people are not eating well, but also because they're not activating their muscles. When muscles aren't used, their cells become resistant to the insulin that the pancreas secretes. That is, the insulin doesn't do its job.

If your muscle cells are resistant to insulin, you have a higher risk of heart disease. And if resistance leads to more glucose going around in the bloodstream, that can cause diabetes.

Q: What if you already have diabetes?

A: In a study by one of my Tufts colleagues on 62 older men and women with the disease, those who had 16 weeks of strength training became stronger, gained muscle, lost body fat, improved their blood sugar control, and lowered their blood pressure.

Even one bout of strength-building exercise will stimulate the muscles to be less resistant to insulin. And there's a whole host of good things that happen when you exercise regularly.

Stronger Bones, Fewer Falls

Q: Does strength training lower the risk of osteoporosis?

A: Yes. Each year after menopause, a woman typically loses one percent of her bone mass--even more during the first five years after menopause. Over time, the bone loss can lead to osteoporosis, when bones are so porous that they can easily break.

Our study followed 40 healthy, sedentary postmenopausal women for a year. Half maintained their usual lifestyle. The others came to our laboratories twice a week and lifted weights.

The women who didn't exercise lost about two to three percent of their bone density by the end of the year. But the women who strength trained gained one percent. The strength-trained group also improved their balance by 14 percent, while balance fell nine percent in the women who didn't exercise.

Q: Can you prevent fractures?

A: Preliminary evidence suggests that you can. More than ten years ago, scientists at the Mayo Clinic randomly assigned a group of 50 women aged 58 to 75 to do strengthening exercises of the back muscles for two years or to serve as controls.

Eight years later, the researchers brought the women back into the lab. Those who had originally been strength training not only had stronger back muscles and better bone density, they also had less than half as many spinal fractures as the control group. That's dramatic.

Q: Muscle loss leads to frailty?

A: And then to dependence. The typical woman who lives into her late 80s, as many women now do, will need about five to ten years of assistance because she's so frail. The same is true for men who live into their 90s.

The frail elderly aren't strong enough to do their grocery shopping or get up and down the stairs or carry out what we call the instrumental activities of daily living. The last thing they want is to end up in a nursing home. They want to drop dead--not now, but much later. Nobody wants to be dependent on others.

Q: So falls often send people to nursing homes?

A: It's one of the leading causes. The odds are 30 percent that a 70-year-old woman will break her hip if she lives to 90. And, depending on the age of the person, 50 to 60 percent of people who break a hip will need care, and 20 to 50 percent will die within a year. If a 65-year-old falls and has a fracture, it can be devastating, but not as devastating as if it's an 85-year-old.

Q: Does the fear of falling make some people inactive?

A: Yes. It's usually because they've had a fall or a friend has had a fall and they see what happens. There's a good reason why they're afraid, but then they become less active and don't go out as much and they get less fit, so they start spiraling downward.

We've done some home-based strength training and balance training. People love the balance training because their improved balance and coordination make them less afraid of falling.

Less Pain, More Sleep

Q: So strength training helps people regain their confidence?

A: That's right. One of the greatest benefits is the sense of self-esteem or empowerment. It happens with both 50-year-olds and 95-year-olds. And they become more active because they're stronger and feel more energetic.

Q: Can the confidence help fight depression?

A: Yes. Many people don't realize that depression is common in older people. It disproportionately affects older people and disproportionately affects older women.

My colleague Maria Fiatarone did a study on 32 older individuals who were moderately depressed. After 10 weeks, those who were assigned to a supervised strength-training program three times a week had quite a remarkable reduction in depression and improvements in sleep and self-confidence.

Since then, we've seen the same reductions in depression in our study in people with arthritis. Other studies have found reductions in depression with aerobic exercise, but Maria's was the first to see it with strength training.

Q: Are sleep problems also common in older people?

A: Yes. Sometimes their internal clock is so out of whack that they're up from three to six in the morning and then they're wiped out so they sleep from four to seven in the afternoon. Everything is off kilter. But with strength training, they sleep deeper, they sleep longer, and they have fewer awakenings.

Q: How does muscle strength reduce arthritis pain?

A: We don't know the mechanism, but we've found that it works with both rheumatoid arthritis and osteoarthritis, which is the leading cause of disability in older adults.

Many people with moderate to severe arthritis have weak muscles. For example, with a knee joint, the hamstrings, the muscle in the back of the leg, is much weaker than the quadriceps, the muscle in front. So the muscles are out of balance. If you strengthen the hamstrings, the knee works better.

Also, when you walk, there is a jarring on the knee joint with each step you take. That's what causes a lot of the pain. When the muscles are stronger and in balance, they absorb more of that shock. They're like the shock absorbers in your car.

We've also seen signs that cartilage degradation goes down and cartilage formation goes up with strength training, but that was just a preliminary study.

Q: Do people improve quickly?

A: They do. I've been here for 21 years, and I think the most rewarding work has been with people who have arthritis. You see them walk better and with less pain. In our study of 38 people with arthritis of the knee, we saw about a 45 percent reduction in pain. A lot of other stuff that we measure, like bone density or glucose metabolism, you can't feel. It's amazing to actually see people feel better.

Q: Does strength training reduce the risk of heart disease?

A: A recent report from the Physicians Health Study showed that men who lifted weights at least 30 minutes a week had a reduced risk of heart disease. We don't have enough women strength training to see if it also protects them.

Q: Does strength training curb back pain?

A: Yes. We haven't done studies on back pain, but others have. Many people who sit at a desk all day, like I do, have weak abdominal and lower back muscles, which is a risk factor for lower-back pain. Strengthening those muscles can reduce the pain.

Q: Do people who do strength training look better?

A: Yes. I tend not to dwell on vanity, but it's wonderful when I hear that a woman all of a sudden starts wearing sleeveless shirts because she's so proud of the way her arms look. Some women start wearing shorts again because their legs have firmed up. Others find that weight control has become easier because their metabolism is a little better.

With any exercise program, many women drop a couple of dress sizes, but with aerobics, you don't get any stronger muscles. Walking is great, but with strength training people get this firmness that they haven't had for years. And they love it.

Q: What about men and middle-aged or younger women?

A: Strength training is important for everyone, except maybe 20-year-old guys. They have so much anabolic hormones floating around, they're going to be strong no matter what.

But that's not true for women in their 20s. It's the last time in their lives where they're still gaining bone. If a woman can step up her peak bone mass then, she can lower her risk of osteoporosis after menopause.

By their 40s, as women are approaching menopause, they start to lose some bone and muscle. Men start to lose, too. So that's also a good time for them to start. Having said that, we've started people strength training at 93 and they gained tremendous benefit. Whatever age you're at is the best age to start.

Q: Can strength training turn back the clock?

A: Yes, but how much depends on your age. With very old people, we see a six to ten percent increase in muscle mass. But they have so little muscle that the actual gain--a pound and a half or so--is small.

I usually say that the 65-year-old woman who's been strength training and doing some aerobic exercise for a year is biologically much more like a 40-year-old woman who is not doing any prescribed exercise.

If the 40-year-old were exercising as much as the 65-year-old, she would be more like the 20-year-old who has been fairly sedentary. So at any age, if you're exercising you're going to be like a younger person who has not been exercising that much.

Q: You said that poor nutrition causes muscle loss. How?

A: About 25 percent of older women are marginally deficient in protein, and some aren't getting enough calories or nutrients like calcium and vitamin D, which is particularly important for muscles.

At any age you need enough protein to keep your liver, heart, muscles, and all other lean tissues viable and healthy. When you don't get enough protein, you start to lose lean tissue, and you lose skeletal muscle preferentially. That leads to frailty.

The first sign is a compromised immune system. People get infections, poor skin, brittle nails, poor hair quality. The body starts shutting down.

It's mostly an issue for frail, homebound older women. They don't eat enough either because it's an economic issue or because they can't get to the supermarket. When you're barely eating enough, the body uses protein for calories, which can lead to a deficiency.

Getting Started

Q: How much strength training do you have to do?

A: The American College of Sports Medicine recommends two to three times a week as optimal, and I agree. If you're consistent with at least twice a week, you get good gains in bone, muscle, everything. Even one day a week is helpful, though not optimal.

Q: How long does it take?

A: About 30 to 45 minutes per session, because you need to do one or two sets of six to 10 exercises.

And it should be moderate to high intensity, so we're not talking about lifting one- or two-pound dumbbells. The weight should be such that you can lift it 10 to 12 times in good form, but after that it feels heavy and you can't lift it correctly. Then you need to rest before you do another set. If you can lift it 15 or 20 times before you rest, the weight is too light. That's more of an endurance aerobic activity, not a strength-building activity.

Q: How much weight should you start with ?

A: It depends. I would start the 50-year-old woman with three pounds for a biceps curl. In a week she'd be up to four pounds. In a couple more weeks, she'd be up to five. And in a few more weeks she'd be up to six pounds. It's a moving target.

When she gets up to 10 or 12 pounds--which is pretty typical because the biceps is a pretty strong muscle--the 10-pound weight will feel like the old four-pound weight did, because her muscles are stronger.

Q: If you can't progress to heavier weights, you're not building muscle?

A: Right. Many women think they can build muscles by lifting soup cans. Or they work out with three-pound weights week after week in a "tone and firm" class. That won't make you stronger. The weights have to be heavier than soup cans. And if you don't keep increasing the load as your muscles get stronger, you won't progress very far.

Q: How many different exercises do you need to do?

A: Six to ten. That's because you need to work different muscles. For example, you can do a biceps curl, which gets at the front of your arms. But you also want to do an overhead press, which gets at the triceps in the back of your arms and the deltoids in your shoulders.

And then you might do a knee extension. You're seated in your chair, you have some ankle weights on, and if you extend your leg out straight, that gets your quadriceps. Then if you're standing and you have ankle weights on and you do a curl back, that gets your hamstrings. That balances the quadriceps exercise.

Then for core strength, you would do some sort of abdominal curl and then a back extension. So you've got six exercises right there (see illustrations). Six is pretty minimal, but it would still be awesome. The big thing is to start.

Q: Can people do it at home?

A: Yes. On my Web site, strongwomen.com, we have animated programs and a free downloadable booklet. Our other site is go.tufts.edu/growingstronger, a program for men and women we did with the Centers for Disease Control and Prevention. It's also animated and downloadable. And fitness centers are now much more receptive to having older adults. Also, many community centers have strength-training programs. And we have Strong Women programs going in 15 states--especially Massachusetts--plus Canada, Australia, and Mexico. You can find a list at go.tufts.edu/strongwomen.

Q: Can people just start on their own?

A: If you're relatively healthy, whether you're in your 40s or early 80s, you can do these programs on your own or at a community site. But the frailer you are and the more complicated your medical condition--for example, if you have severe osteoporosis or arthritis--the more important it is to talk to a physical therapist or personal trainer to customize your own program. You don't want to do any harm.

We work with almost anybody. But if you have some significant medical condition, you want to make sure you're doing the exercise in the correct form.

Q: Do people push themselves enough to build strength at home?

A: It depends on the person. We did a study on frail elders--they were in their late 70s--and they did the whole program at home on their own. Their brute strength didn't change a lot, but their balance got better and they improved on national standardized tests that look at elderly function like chair stands. So we were thrilled and so were they.

Q: What about men?

A: Everything applies to them, too. Most of our studies include both men and women. But there are some differences.

Men naturally have more muscle and they don't live as long, though that's changing. More men are living to advanced age, but they get a little reprieve. Things like osteoporosis start happening about a decade later to men than to women. And diabetes and arthritis disproportionately affect women.

Q: Is it better if someone pushes you to lift more weight?

A: With anything you do, it's nicer to have somebody helping you out. That's why we try to get people to exercise with a friend or neighbor. You can gab and catch up. And instead of just drinking coffee, you get strong together. Or find a community program, because it's nice to socialize as well.

Q: Is it better to lift weights very slowly?

A: Super-slow strength-training techniques have been around for years. Apart from anecdotal reports, there has been no published research on them. At Tufts University, we use about six to eight seconds for each repetition, which is slow, but not super-slow.

I believe that the super-slow technique, which takes 15 to 20 seconds for each repetition, is perfectly safe and effective. Most people strength train at too fast a pace, which makes their training much less effective. The super-slow method forces people to concentrate on their form and on feeling the movement of their muscles as they lift and lower the weight.

But the super-slow pace can be monotonous for some people and can cause more muscle soreness than is necessary. Also, because each exercise takes so much longer, a super-slow pace usually means that you do only a few exercises.

So if you want a slower pace for variety's sake, just make sure that you do at least six to 10 different exercises and that you leave some time for aerobic exercise.

Aerobic Exercise

Q: Is aerobic exercise less important than strength training?

A: I would never say that strength training is much more important than taking a walk. It's like asking me which of my three kids is my favorite.

All physical activity is critical for healthy aging and good health at any age. It's just that as we get older, the loss of muscle becomes more critical, so strength training takes on a more important role.

Q: What's the minimum for aerobic exercise?

A: It's a stepwise process. You may start with just 10 minutes three times a week. But you want to work up to at least 30 minutes of moderate exercise on most days and some vigorous activity mixed in at least two or three days of the week.

Q: Is brisk walking moderate?

A: It depends on how old you are. For a frail elder, slow walking is moderate. For a 20-year-old, running is moderate. For most 40- or 50-year-olds, it's brisk walking.

Vigorous exercise means brisk walking for an elderly person, maybe jogging for the 50-year-old, and running faster or uphill for the 20-year-old.

Q: Doesn't aerobic exercise burn more calories than strength training?

A: Yes. But strength training helps improve basal metabolism and promotes more muscle mass and bone. The older you get, the more important strength training becomes. But in the end, it's about exercising ... any kind.

Biceps Curl with Rotation

* Sit toward the front of the chair with feet flat on the floor, one dumbbell in each hand, with forearms extended straight down at your aides, palms facing your thighs.

* Exhale and slowly raise the dumbbell in one hand towards your shoulder by bringing your forearm up. Rotate your forearm as you lift, so that your thumb turns toward the outside of your body. Pause for the count of one.

* Inhale and slowly lower the dumbbell. rotating your arm so that your palm faces your thigh in the starting position.

* Pause for a breath and then repeat the move with the opposite arm. That completes one repetition (rep).

* Perform 8 reps, rest for 1-2 minutes, then perform a second set of 8 reps.

Seated Overhead Press

* Sit toward the front of the chair with feet flat on the floor, one dumbbell in each hand, held at shoulder height parallel to the floor, with the inner ends touching the front sides of your shoulders.

* Exhale as you slowly lift the dumbbells straight over your head. Don't lean backward. Extend your arms completely so that they are straight up. Hold the lifted position for the count of one.

* Inhale (for a count of four) as you slowly lower the dumbbells until they are just outside of your shoulders, back in the starting position. Pause for a deep breath. That completes one repetition (rep).

* Perform 8 reps, rest for 1-2 minutes, then perform a second set of 8 reps.

Knee (or Leg) Extension

* Strap ankle weights on both ankles.

* Sit all the way back in a chair without slouching, your legs separated slightly so that your knees and feet are hip-width apart. Your thighs and lower legs should form a 90-degree angle. Place your hands on the tops of your thighs or on the sides of the chair.

* Exhale as you lift your right leg in a slow, controlled movement (to the count of two). Lift until your knee is straight (but not locked). Hold your leg in the lifted position for the count of one.

* Inhale as you slowly lower your right leg (to the count of four), until your foot rests on the floor, back in the starting position. Pause for breath.

* Repeat with your left leg. That completes one repetition (rep).

* Perform 8 reps. rest for 1-2 minutes, then perform a second set of 8 reps.

Knee (or Leg) Curl)

* Strap ankle weights on both ankles.

* Stand very close behind the back of a chair, holding the back lightly for support, your knees lightly touching and the front of your thighs even with one another.

* Shift your body weight so that you're standing on your left leg.

* Slide your right foot back approximately 6 inches until only the toes are in contact with the floor.

* Exhale as you lift your right foot up and back until your thigh and lower leg form a 90-degree angle. Hold your leg in the lifted position for a count of one.

* Inhale as you slowly lower your right foot just until the toes are in contact with the floor. Then slide the toes forward to the starting position. Pause for a breath.

* Repeat the move with your left leg. That completes one repetition (top).

* Perform 8 reps, rest for 1-2 minutes, then perform a second set of 8 reps.

Abdominal Curl

* Lie on your back on the floor, knees bent and feet flat on the floor. Place your hands behind your head, elbows pointing out.

* Exhale as you slowly raise your shoulders and upper back off of the floor (to the count of two). Keep your chin lifted toward the ceiling and your elbows pointed out. Don't pull on your head or neck with your hands. Pause.

* Inhale as you slowly lower your shoulders and upper back down to the floor (to the count of two), back to the starting position. That completes one repetition (rep).

* Perform 10 reps, rest for 1-2 minutes, then perform a second set of 10 reps.

Back Extension

* Lie face down on a mat with your legs straight and your toes pointed so that the laces of your sneakers face the floor. Extend your left arm straight forward, palm facing the floor. Extend your right arm down at your side.

* Exhale as you slowly raise your left arm and right leg as high as you comfortably can. Lift the leg from the hip and keep it straight, and lift both shoulders and upper chest off the floor. Pause for the count of one.

* Inhale as you slowly lower your left arm and right leg back down to the floor, to the starting position. Pause for a breath. That completes one repetition (rep).

* Perform 8 reps of left arm/right leg lifts, followed by 8 reps of right arm/left leg lifts. Rest for 1-2 minutes.

* Perform a second set of 8 reps on each side.

Miriam Nelson is director of the John Hancock Center for Physical Activity and Nutrition at Tufts University's Friedman School of Nutrition Policy and Science in Boston and the author of several books, including Strong Women Stay Young, Strong Women and Men Beat Arthritis, Strong Women Stay Slim, and Strong Women, Strong Bones. She spoke to NAH's Bonnie Liebman by telephone.