Carrying some extra weight around can be good for you—if those added pounds come in the form of dumbbells or ankle weights. Strength training offers benefits that range from weight loss to reducing arthritis pain, studies show.
"The muscles in our bodies are critical to our overall health, and by strengthening them we can ward off chronic diseases like obesity, osteoporosis and diabetes," says Miriam Nelson, director of the Center for Physical Fitness at Tufts University in Boston and the author of several books on strength training.
Strength training's major benefit is the role it plays in weight loss. "Most people don't understand that muscles regulate body weight by regulating metabolic rate," Nelson says. Lifting dumbbells, working out on weight machines at the gym, or doing pushups at home help maintain and increase muscle, which raises the metabolism and increases the number of calories the body burns.
Simply put, the more muscle you have, the more calories your body burns—as much as 7 percent more a day, according to a University of Maryland study. "That's why strength training is critical for people with a weight-control problem," Nelson says. Weight training is especially important as we age, she adds, because beginning in their mid-30s, people lose about one-third pound of muscle a year and may begin gaining weight as a result.
Many women mistakenly believe lifting weights will result in a masculine-looking body. However, testosterone plays a key role in muscle development. Unlike men, women have very little of this hormone, so they don't "bulk up" the way men do.
"Women won't bulk up and look like Miss Olympia with strength training," Nelson says. "Fat is actually more bulky than muscle, so it takes up more space. A pound of muscle is about 30 percent smaller than a pound of fat." In fact, Nelson's research shows that most people who lift weights lose fat as they gain muscle and often drop one or two sizes in clothing.
Strength training can also prevent the effects of aging in pre-menopausal women and reverse the effects in post-menopausal women. A study published in the Journal of the American Medical Association reported that post-menopausal women reduced body fat, increased muscle mass, built up bones, and improved balance by lifting moderately heavy weights on a regular basis.
The benefits of strength training aren't confined to the overweight or to women and older people. It lowers the resting heart rate, decreases resting blood pressure and increases blood levels of HDL (the so-called "good" cholesterol). It improves posture, helps guard against lower back injuries, improves balance and coordination, and has been shown to reduce pain associated with arthritis.
Weight training also plays an important role in boosting self-confidence and body satisfaction. "Our muscles give us our body shape," Nelson says. "With strength training you can change that shape."