Biomarkers of Aging, Metabolic Rate, and Aerobic Capacity
Live Like You Can
By Janis McDonald
Last month, I shared the1992 study by Williams Evans, PhD and Dr. Irwin Rosenberg (Tufts University USDA Nutrition Research Center on Aging) that caused a paradigm shift in the thinking about how we age and how strength training can postpone and even prevent entry into the disability zone. The male participants were in their ninth decade and over a 12-week period were given intense strength training exercises. The men gained an average of l73 percent upper body strength and 400 percent lower body strength.
Dr. Evans states, “My book, Biomarkers: The 10 Keys to Prolonging Vitality, is based on my hypothesis that these 10 biological markers that have been thought to occur as a result of chronological age are, in fact, a product of how we live our lives. These biomarkers include muscle mass, strength, resting metabolic rate, aerobic capacity, blood pressure, insulin action, HDL to total cholesterol ratio, bone density, and ability to control body temperature.”
The study strongly supported the idea of the first two biomarkers (strength and muscle mass) as being the critical foundation for the remaining ones. Last month, this column explained the reasoning behind this statement. Now let’s take the next two biomarkers, resting metabolic rate and aerobic capacity, and discover how these two aging events can also be altered and slowed with sufficient strength training and exercise.
The loss of muscle mass and an increase in fat mass has long been associated with aging. The loss of muscle due to lack of use is accompanied with a reduction in resting metabolic rate (RMR). RMR is the minimum rate of energy required to sustain vital functions at rest. An ever-decreasing RMR can lead to slow weight gain and obesity. Continuing studies have shown heavy strength training increases both muscle mass and RMR.
Still, it is clear that more research is needed to determine customized protocols that address the specific circumstances of elderly individuals. However, strength training has been proven to benefit all persons of any age, and research also shows intelligently prescribed strength training can greatly improve the quality of life for the older individual.
Aerobic capacity is the maximum amount of oxygen that the body can utilize during an exercise session, usually measured during a brief period of high-intensity exercise. As we age, we will lose aerobic capacity starting in the 20s and 30s with a three to six percent loss, and by the seventh decade, the loss can be as much as 20 percent. Despite the inevitability of aerobic fitness decline, exercise is still critical in living an independent life into old age. In fact, older adults that increase leg strength will be able to perform aerobic exercising training at a greater intensity or for a longer duration, leading to improvements in aerobic capacity.
Stay tuned! The Live Like You Can column will next explore how strength training and muscle mass effect blood pressure and insulin action.
Janis McDonald, Professional Wellness Coach, Private Personal Training Gym,
152 0457. Follow the Live Like You Can Blog! Go to: www.livelikeyoucan.com