I'm an exercise junkie - and proud of it. I swim, I run, I bike.
But, like many other people, I'm a disaster when it comes to lifting weights, also called strength, or resistance, training. The closest I come is lifting a few tiny dumbbells at home in front of the TV. And that's only when the Red Sox are on.
This is about to change, and not just because of lingering New Year's resolutions.
A growing body of evidence shows that strength training not only provides many benefits that aerobic workouts alone cannot, but also offers some of the same health benefits as aerobic conditioning.
It's long been known that weight lifting becomes more important as you get older to prevent injury and preserve the strength to do normal things like climbing stairs, hauling groceries, and chasing grandchildren.
What's comparatively new is that it does much more than that, potentially reducing the risk of developing heart disease, relieving neck pain, improving balance, and making it easier to battle the bulge - though it needs to be done properly to avoid injury.
The evidence for the value of strength training has grown so much that last year, the American College of Sports Medicine and the American Heart Association issued new recommendations for healthy adults 65 and older that stressed the importance of weight lifting.
The groups now recommend that all older Americans do eight to 10 repetitions for each of the major muscle groups (biceps, quadriceps, hamstrings, etc.). Resistance exercises should be done on two or more nonconsecutive days of the week.
The idea is to lift a weight that's heavy enough to work each muscle group until it is fatigued, so the amount you lift will increase as your strength grows. Weight-bearing exercise, like walking or running, does not count as weight lifting - that means you really have to lift weights or work out on a resistance machine.
One of the biggest benefits of strength training is that it dramatically increases muscle mass, which aerobic exercise does not, noted William J. Evans, director of the Nutrition, Metabolism, and Exercise Laboratory at the University of Arkansas for Medical Sciences. More muscle mass is good not just because it makes you stronger but because it increases basal metabolic rate - muscle cells even at rest burn more calories than fat cells.
Moreover, while aerobic exercise can significantly, although temporarily, increase blood pressure, a potential concern for some heart patients, resistance training does so only minimally, Evans said. Weight training also gets results fast - it only takes resistance training twice a week for a few weeks to begin to see a significant effect, compared with three days a week with aerobics.
Indeed, the more researchers probe the benefits of weight training for specific conditions, the stronger the case they can make, said Miriam Nelson, director of the John Hancock Center for Physical Activity and Nutrition at Tufts University.
Although studies have not yet proven that strength training lowers the risk of osteoporosis, Nelson said, they do show it lowers the risk of fractures by improving balance, bone density, and muscle mass. Weight training is also good for people with arthritis, she said, because stronger muscles can take the pressure off inflamed joints.
Weight training has been shown to have other benefits, too.
Research by Steven N. Blair, an exercise scientist at the University of South Carolina, suggests that people with greater muscle strength may be somewhat less likely to develop metabolic syndrome, a cluster of factors that raise the risk of heart disease and diabetes, such as increased waist size, high fasting blood sugar, high triglycerides, low HDL or "good" cholesterol, and high blood pressure. More studies are needed to confirm this association.
For older people with physical disabilities, 66 trials reviewed by Cochrane Collaboration, an international nonprofit group that evaluates health treatments, increasing strength and, to a lesser extent, function. A different 2007 Cochrane review of 34 studies showed that exercises, including strength training, can improve balance in women age 75 and older. Yet another 2007 Cochrane review of 34 studies on fibromyalgia (musculoskeletal pain) showed strength training may improve physical capacity.
And a Danish study just published last week showed that strength training can diminish the chronic neck pain of at computers.
I could go on. But I'm convinced. Weight training may not be as much fun as a run in the park. But I need it. I'm guessing you do, too.