- muscle mass
- bodyfat percentage
- aerobic capacity
- blood sugar tolerance
- TC / HDL ratio
- blood pressure
- bone density
- body's thermoregulatory ability
Typically, the older aging inactive adult experiences the following adverse changes in their biomarkers: decreased muscle mass and the associated reduction in strength that comes with it; reduced BMR; increased bodyfat percentage; decreased aerobic capacity; reduced blood sugar tolerance; increased TC/HDL ratio; increased blood pressure; decreased bone density; and decreased ability to regulate internal body temperature. Sounds like doom and gloom but these biomarker trends are not inevitable. You can reverse the trend by being more active as you grow older. A lifestyle of regular exercise consisting of strength training and aerobic conditioning will favorably affect all of the aforementioned parameters.
Of paramount importance is maintaining, if not increasing, your muscle mass. Sarcopenia, a condition in which a sedentary lifestyle enables muscle to waste away, is insidious. Dare I say it here, "If you don't use it, you lose it". Your fast-twitch muscle fibers (primarily responsible for strength and involved in heavy lifting and quick movements) will be the first to atrophy because your body does not need these muscle fibers to survive. As muscle is lost, fat is gained. The combination of less muscle mass and more fat accumulation inevitably decreases one's strength level. Weight lifting will enable you to gain muscle mass because muscle tissue hypertrophy (i.e., increased muscle size) occurs when put under stress.
Naturally, as you gain muscle mass you will gain strength because a larger muscle means a stronger muscle. In addition, an increase in muscle mass causes your BMR (basal metabolic rate) to increase because muscle is a highly metabolically-active tissue. As BMR increases, your body becomes much more efficient at burning fat for fuel. The best part: as you get older, you can eat just as much food as when you were in your twenties without getting fat as long as you lift weights to maintain your muscle mass.
It's not about how much you weigh that matters--rather it's about how much fat and muscle mass you have on your body. In other words, it's about your body composition that matters more than your bodyweight. Remember, muscle weighs more than fat. So if you gain muscle mass, your bodyweight may actually increase! Don't be alarmed. Even though you may gain weight, you will appear leaner when you gaze at your body in the mirror.
Aerobic conditioning will ameliorate the normal decrease in your aerobic capacity (i.e., VO2-max) that occurs with aging because your heart, lungs and capillaries will become more efficient at processing oxygen within your bloodstream. In addition, the oxidative capacity within your muscles will increase by virtue of the increased demand of having more muscle mass.
Performing weight lifting in conjunction with aerobic conditioning will lessen your body's insulin resistance, paving the way toward increased blood sugar tolerance. This means that your body will process sugar more readily when your body is more muscular. The less bodyfat (and more muscle) you have, the more insulin sensitive your body will be. Increased insulin sensitivity within your body decreases your risk of hyperlipidemia (high cholesterol), hypertension (high blood pressure) and heart disease. In conjunction with strength training exercise, a low-fat, high-fiber diet will also boost your body's insulin sensitivity.
Losing fat around your midsection is an important determinant of your risk of particular chronic diseases such as heart disease, stroke and diabetes. With respect to diabetes, when you retain more fat in your belly, your body becomes less insulin sensitive. This in and of itself increases your risk of diabetes. Whereas, gaining more muscle mass will increase your muscles' capacity to store glucose in the form of glycogen (your body's sugar fuel for energy) and therefore increase your body's insulin sensitivity.
Your TC / HDL ratio will decrease because exercise and losing bodyfat will raise your HDL (high-density lipoprotein) level. Your HDL (good cholesterol) level is what really matters rather than your TC (total cholesterol) level in terms of your risk of heart disease, stroke, etc.
Your blood pressure will decrease because increased physical activity in conjunction with a low-fat, low-salt diet will increase arterial pliability and boost your heart's blood pumping efficiency.
Weight training and/or weight-bearing exercise (e.g., walking, jogging, etc.) will increase your bone density because bone (which is living tissue) put under regular loads decreases porosity. Getting adequate calcium and vitamin D in your diet with possible supplementation is also recommended.
Your body will begin to regulate its internal temperature more efficiently when you're more active because of increased blood flow and metabolic rate. Regular exercise increases the water content within your blood provided you adequately hydrate. When blood flow increases, your body is better able to sweat and thus cool itself via evaporation in hot temperature environments. When your metabolic rate is elevated, your body is better able to shiver and thus heat itself in cold temperature environments.
BOTTOM LINE: It's never too late to reverse the health consequences (i.e., heart disease, cancer, hypertension, stroke, diabetes, obesity, osteoporosis, etc.) of living a sedentary lifestyle. Lifting weights and performing cardio exercise (e.g., walking, swimming, biking, etc.) regularly will reverse the adverse biomarker trend of living a nonactive lifestyle and therefore slow the aging process to enable you to live a fuller, quality life!
Brian Danley, CFT
"Motivation is what gets you started. Habit is what keeps you going."