Impact of Endurance/Resistance Training on Skeletal Muscle Glucose Metabolism in Older Adults

Endurance training is what we refer to as aerobic exercise. It may involve bicycling, it may involve walking on a treadmill, or using an elliptical. In contrast, resistance training involves pumping iron, resistance bands, or even your own body weight.

1. Age and Insulin Resistance
   1. It is estimated that 30% of individuals over the age of 60 are affected by type 2 diabetes.
   2. Aging has been associated with glucose intolerance and whole-body insulin resistance.
   3. multifaceted including chronological age, reduced physical activity, inflammation, and/or increased body fat.
   4. Since skeletal muscle is the primary target for insulin-mediated glucose uptake, age-related changes in the structure and metabolism of this tissue are also thought to play a major role in the pathogenesis of insulin resistance in older adults.
   5.  
2. Age and Skeletal Muscle Atrophy
   1. Age-associated muscle atrophy begins as early as 25 years of age and accelerates thereafter, so that, by 80 years of age, approximately 40% of the vastus lateralis (muscle in the thigh) has been lost.
   2. Much of the current literature discussing the age-related loss of muscle mass (termed sarcopenia) focuses on the adverse effects to muscular strength and power, leading to loss of mobility and the inability to perform daily activities, including climbing stairs and lifting objects.
      1. While these are obviously critical concerns, it should also be noted that sarcopenia is thought to have harmful effects on glucose uptake, since it reduces the amount of available muscle mass for insulin-stimulated glucose disposal.
   3. Physical Activity, Exercise, and Insulin Sensitivity in Older Adults
      1. Physical activity has long been associated with superior health and enhanced quality of life in individuals of advancing age.
      2. declining physical activity with aging is a main contributing factor in determining the degree of age-related insulin resistance.
   4. Effects of Exercise Training on Skeletal Muscle Tumor Necrosis Factor (TNF)-Alpha in Older Adults
      1. the aging process is associated with increased inflammation, which contributes to age-related insulin resistance
      2. Skeletal muscle tumor necrosis factor (TNF)-alpha, an inflammatory marker, has been reported to be increased in aged individuals compared to their younger counterparts.
      3. A direct link between TNF-alpha and impaired skeletal muscle insulin signaling and glucose uptake has been established.
      4. Resistance training or a combination of resistance, endurance, and flexibility training has been proven to decrease skeletal muscle TNF-alpha levels in the elderly.
      5. Reductions in TNF-alpha or other inflammatory markers could contribute to the exercise-induced improvements in insulin sensitivity in older adults.

Obesity causes frailty in older adults; however, weight loss might accelerate the age-related loss of muscle and bone mass and resultant sarcopenia and osteopenia. Weight loss plus combined aerobic and resistance exercise is the most effective in improving the functional status of obese older adults.

The take-home message here is that adding resistant training will enhance your health and improve the quality of your life.

Impact of Endurance/Resistance Training on Glucose Metabolism in Older Adults

Endurance training is what we refer to as aerobic exercise. It may involve bicycling, it may involve walking on a treadmill, or using an elliptical. In contrast, resistance training involves pumping iron, resistance bands, or even your own body weight.

1. But, did you know that as we get older, we start to develop insulin resistance that leads to type 2 diabetes?
2. Did you know we start to lose muscle mass at age 25?
3. Did you know that declining physical activity with aging is a main contributing factor in insulin resistance?
4. Did you know the aging process is associated with increased inflammation, which contributes to age-related insulin resistance?

By understanding the effects that glucose metabolism has as we age, we can then learn the positive impact that endurance training and resistance training can have on reversing or maintaining glucose metabolism and muscle mass as we age.