According to nearly 80,000 responses gathered by the Pennington Biomedical Research Center in Baton Rogue, Louisiana, on any given day less than half of U.S. adults engage in what's considered by the Metabolic Equivalent (MET) intensity values "moderate activity," and the most frequently listed moderate activity for those who did was can you believe it? food preparation.

Since when did scooping coffee, scrambling eggs, and chopping onions constitute a workout?But there's another stat from the report published in the October issue of the American Journal of Preventive Medicine that's even more disheartening: only one out of every 20 U.S. adults engages in what's considered "vigorous activity."Of the paltry 5 percent who do, 3.3 percent do some sort of aerobic activity. That means as low as 1.7 percent do what I believe is absolutely essential for optimal, long-term health.Lift weights.In the past, I've called weightlifting the best overall exercise, and one of the reasons is that it's more versatile than duct tape. For instance, every high school athlete regardless of sport or sex could benefit.A female cross-country runner's program might even include many of the exercises found in a football player's. The difference? Far less weight and far more repetitions.Yes, even in sports where additional muscle would be deleterious like distance running, increasing one's strength-to-weight ratio through weightlifting allows formerly fragile runners to flourish rather than fade near the finish line.And weightlifting aids all non-athletes whether young or old. That means a 60-year-old grandfather and his 16-year-old grandson can work out together.Several studies have shown people in their 80s and 90s who begin a weightlifting regiment nearly double leg strength while other muscle groups get nearly as strong.Other studies have dispelled the myth that children should not lift weights until after puberty. As long as the number of repetitions per set remains high in the 12-15 range and proper form is used, no damage to tendons, ligaments, or bones occurs.Another reason why I've lauded lifting weights is efficiency.The most common excuse given for why more people don't workout is lack of time, which for certain activities is a legitimate excuse.To prepare for bicycle racing, for example, I ride between 12 and 15 hours a week. Even veteran walkers who seek improved fitness should walk 5-6 hours a week with one workout of more than an hour.But for those with other commitments that make those time investments impossible or impractical there is weightlifting.After a four- to six-week acclimation period where learning the movements and employing lengthy recovery times lengthen the workouts, sessions should be limited to 45 minutes no more than four times a week. In fact, longer or more frequent workouts are often counterproductive.And on those days when your lifting is more aerobic in nature, a 20- to 30-minute non-stop workout is sufficient for general conditioning.But all those general arguments above are from the past, and if the aforementioned study is correct, they didn't do much good. So I'd like to get a bit more specific today and give three reasons why one specific group, middle-aged women, should be lifting weights right now:1.) The holiday season is approaching;2.) winter follows;3.) you're at the age where you naturally lose muscle mass.Near age 30, all bodies begin to naturally lose muscle mass. If you don't lift weights, the loss can be as high as one percent per year by age 45.That means that a health-conscious 135-pound, 35-year-old, fit female who diets and does aerobics to remain at 135 pounds could be carrying as much as seven or eight pounds less muscle 10 years later which means seven or eight more pounds more of fat.But weightlifting can negate much of that change in body composition.And don't forget that muscle burns calories, but fat is inert. The aforementioned female at age 45 would need to eat about 500 calories less per day to maintain her weight because of muscle loss.The time of year also factors into why women should be lifting weights right now. While just about everyone likes to relax their diet and enjoy the traditional foods served at Thanksgiving and Christmas, many would rather not do the eventual additional exercise required to undo the damage.Lifting weights ahead of time helps with that more than aerobic exercise.That's because studies have found that while both expend significant amounts of energy during exercise, weightlifting burns more than aerobic exercise afterwards. In an old study led by Carol A. Binzen, a clinical exercise physiologist at Johns Hopkins University, subjects burned on average 50 additional calories in the two hours after 40 minutes of aerobics, 50 calories more than their typical basal metabolic rate while at rest.The women who lifted weights, however, burned an average of 155 calories in the two hours of rest immediately afterwards.Furthermore, as your body composition changes and you add muscle, you'll burn more calories naturally, all day. That's because, as mentioned before, muscle needs calories; fat is inert.The final way that the change of seasons makes weightlifting even more practical is the sometimes harsh weather and lack of daylight. Both keep the occasional runner or walker inside from time to time and less active.