The human body did not evolve to its present state of exalted beauty, superlative grace and unequaled capability by adhering to a rock like a barnacle. Our ancestors did not lounge around in front of the campfire all day, rising only to fetch conveniently packaged, ready-to-eat chunks of Woolly Mammoth from the ice box. Like it or not, two or three generations of desk jobs can't eradicate millions of years of evolution.
In recent years, scientific investigation of human physiology and performance enhancement has subtly transformed the notion of "healthy." Fortunately, this metamorphosis has infiltrated cultural bias, including our subjective perceptions of beauty. But, as anyone over the age of 20 will rapidly attest, a lean, toned, tantalizing physique does not just happen. A growing stockpile of scientific data has finally confirmed what any active person could have told you decades ago: the mental and physical benefits of regular physical activity, especially strength training, are legion!
It's as simple as that. Muscle is one of the most metabolically active tissues in the body. Fat, on the other hand, requires almost no energy expenditure to survive. The more lean tissue (muscle mass) you possess, the more calories you will burn all day, every day, regardless of your activity level. First, contracting your muscles requires substantial caloric expenditure, so every time you train, you are burning calories. Second, exercise transiently raises your metabolic rate for several hours following each session so, you continue to burn extra calories even if you're just lying on the couch watching TV. Finally, studies have demonstrated that each pound of muscle that you possess requires approximately 35 calories per day just to exist. The more muscle you possess, the higher your resting metabolic rate, and the greater your overall caloric expenditure. Research indicates that for every 3 pounds of muscle gained by the average individual, resting metabolic rate increases by 7 percent and daily caloric requirements increase by 15 percent.
Adults who do not engage in regular resistance work will typically lose between five and seven pounds of lean mass every ten years. Although aerobic exercise improves our cardiovascular health and stamina, aerobic exercise alone cannot prevent age-related muscle loss. This fact alone has enormous bearing on why people tend to gain weight as they age. If, for example, a given individual were to lose five pounds of muscle over a decade, that would translate to roughly 175 fewer calories that individual would expend each day. Assuming this individual's activity level and daily caloric intake were to remain constant over the ten years of gradual muscle atrophy, that would add up to a fat gain of over 15 pounds during the tenth year alone!
Although strength training does not substantially improve your cardiovascular fitness, (that's what aerobic activity is for,) it does, never the less, seem to have a very positive impact on cardiovascular health. In several related studies, regular strength training correlated to a reduction in both resting blood pressure and circulating triglyceride levels.
Just about every vigorous physical activity works to increase gut motility while decreasing intestinal transit time (i.e. the time it takes for food to travel through your body). Strength training is no exception. According to several studies, the less time that waste products linger in your bowel, the less likelihood that you will ever develop colon cancer.
Weight training not only increases strength and muscle mass, it also enhances the strength of connective tissues, resulting in more resilient joints. Possessing stronger, more stable joints decreases your risk of injury. Strong muscles and joints are also essential to preventing the degenerative changes that can lead to osteoarthritis. But what if you already suffer from degenerative joint disease? According to several studies, moderate strength-training, (probably by virtue of its joint-stabilizing effects,) actually helps ease arthritis pain. Resistance work and weight bearing exercises are perhaps the single most effective way for a woman to prevent, and even reverse, the age-related decline in bone mineral density which can culminate in crippling osteoporosis.
Strength Training could even save your life! Considering the collection of sordid characters one is bound to encounter during a lifetime, (many of whom are men and will be bigger than you,) it's extremely empowering to realize that you possess the strength and confidence to put up a genuine fight, should the need ever arise. Sociologists have demonstrated that a woman who moves with confidence is less likely to be singled out by a mugger or rapist as a prospective target.
Dr. Christine Lydon is the author of a new book, "Look Hot, Live Long," (Basic Health Publications; 2003, $14.95). For more information on her book, visit the website: www.letsliveonline.com (click on Basic Health Publications) or to order the book, call 1-800-575-8890.