Biomarkers are measures of various significant biological states, used to monitor our health. They are also the best way to track the effectiveness of efforts to slow down aging. As this quick review of current biomarker research shows, strength training is the key.
1. Muscle Mass. Muscle mass is the most important of the 10 biomarkers. You lose it at a rate of 0.5 lbs./year or 5 pounds per decade starting at age 40. Strength training can offset this critical loss of lean muscle tissue known as sarcopenia. One study examined the lean muscle mass of master athletes aged 40 to 81 years. The researchers found that those training 4 to 5 days per week had no significant decrease in strength with age and no loss in total lean mass4
2. Strength. As you lose muscle mass, the cross-sectional size of the muscle decreases and balance and strength are subsequently lost. A 12-year longitudinal study by Tufts University found that knee and elbow flexors and extensors lost 20 to 30% of their strength between the ages of 55 and 65 years1. Regular strength training can retard such losses.
3. Basal Metabolic Rate (BMR). As you age, your metabolic rate declines due to a number of factors including a loss of metabolically active lean muscle. Strength training builds muscle over time and each pound of new muscle requires an additional six calories to maintain (compared to 2 calories per pound of fat). Eating more protein with each meal and drinking more cold water will also temporarily speed up your metabolic rate.
4. Body Fat Percent. The average person adds body fat as they age. Consistent exercise and sound nutritional intake can help offset this change. Strength training is critical for maintaining the appropriate ratio of muscle and body fat. Body-fat levels should be kept below 25% in men and 32% in women. College age (non-athlete) men typically carry 15% body fat while females have 23%.
5. Aerobic Capacity. Aerobic capacity refers to how your body can process oxygen in a given amount of time. Maximum oxygen intake starts to decline at age 20 in men and age 30 in women. By the time both sexes reach age 65, aerobic capacity will be 20-30% less compared to young adults. But your aerobic capacity can improve over time with consistent, challenging aerobic and circuit-based strength exercise. For instance, research demonstrates that 12 weeks of strength training will increase treadmill walking endurance by 38% in women 65 to 79 years old3.
6. Blood-Sugar Tolerance. As we age we have a harder time managing our blood sugar (or glucose) levels because our bodies gradually lose the ability to use the sugar that is circulating in our bloodstream. By age 70, 20% of men and 30% of women have an abnormal glucose tolerance curve2 and this can lead to type 2 diabetes. Strength training helps regulate glucose metabolism, keeping the curve in the healthy zone.
7. Cholesterol/HDL Ratio. Your total cholesterol divided by your good (HDL) cholesterol will give you your ratio and this number should be 4.5 or lower. Exercise, diet and good genes all play an important role in keeping the ratio low.
8. Blood Pressure. High blood pressure can be caused by a multitude of factors including obesity, high intake of fat, alcohol, smoking, hereditary disposition, and too little exercise. One study showed that 16 weeks of strength training by 60-to 77-year-old women significantly decreased heart rate and blood pressure5.
9. Bone Density. As a person continues to age, there is a normal decline in the mineral content of bones. This process ultimately leaves an older person with a weaker, more brittle skeletal system. The average person will lose 1% of bone mass each year2. It is well understood that physical activity improves bone mineral density while building strength and muscle mass in elderly women6. Strength training helps offset this loss.
10. Internal Temperature Regulation. Older people sometimes experience unhealthy lower body temperatures. The good news is regular exercise can help repair the body’s temperature-control mechanism. The key to internal temperature regulation is fluid intake. In other words, as you age, make sure you hydrate.
All ten of these important biomarkers can be improved through strength training. Muscle mass and strength are the primary biomarkers, the lead dominos, so to speak. When they start to topple, the other biomarkers soon follow. On the other hand, when muscle mass and strength are maintained, the other biomarkers are likewise maintained. Aerobic exercise and diet are important, but if you really want to stay youthful into old age, strength training is crucial.
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About Michael Wood, Chief Fitness Officer
Michael Wood, CSCS, is Chief Fitness Officer at Koko FitClub, driving the development of integrated strength and cardio training and nutrition programs for Koko members nationwide. A nationally acclaimed fitness expert, Michael has conducted research as a Senior Exercise Physiologist at the Nutrition, Exercise Physiology and Sarcopenia Laboratory at the Research Center on Aging at Tufts University, and has lectured at Boston University and the University of Connecticut. He has been named Boston Magazine’s “Best of Boston” Personal Trainer, and made the Men’s Journal “Dream Team” list of the nine best trainers in the U.S. Michael and his family live in North Attleboro, MA.