Metabolism: How Muscles are the Keys!
You may be surprised to know that between ages of 30-50 we lose approximately 5 pounds of muscle per decade (Evans and Rosenberg 1992) and after age 50 we lose 10 pounds of muscle per decade!!! (Nelson et al. 1994). Crazy right?! This is an unfortunate fact that has really made me become passionate about the importance of helping people develop their muscle mass. I was going to originally write a blog about the health benefits of resistance training, but quickly realized that it will take multiple blogs. I want to address weight management first - not because I think it is the most important thing, but because the fact of the matter is that in the back of people’s minds is often the idea of either wanting to lose, maintain or gain weight. As such, you’ll be interested to know how resistance training can help.
Resistance training creates changes in body composition, and this can affect metabolism: Increased muscle mass means that there is a change in body composition (percentage of fat vs muscle). If a person has the objective of losing weight - it is a healthy goal to work on increasing muscle mass in the process. Why? When people diet to lose weight and only adhere to cardio, together with fat, people also inevitably lose muscle mass. In later blogs, I will describe the importance of increased muscle mass on the prevention and management of degenerative diseases (Baechle and Westcott 2010) and why as such it is a good idea to try to prevent muscle loss - in fact try to increase muscle, when trying to lose weight, or wanting to maintain or gain weight.
When people want to lose weight, they often resort to highly restrictive diets which they obviously tend to keep for short periods of time as they are usually not physically and psychologically sustainable. As they diet, metabolism slows down and without resistance training, muscle mass decreases (and this decrease is also in addition to the natural age related muscle mass decrease). The weight lost with the typical restrictive, calorie reduced diets is composed of about 25% muscle tissue loss (Ballor and Poehlman 1994) which in turn slows down metabolism. Inevitably, people can’t function on restrictive, low calorie diets forever. In fact, as per Brehm and Keller 1990, less than 5% of those dieting are successful! Mann et al, 2007, did a comprehensive review of weight loss research that was published by the American Psychological Association and observed that basically all individuals who lost weight by dieting regained it! When restrictive dieters go back to more normalized eating, with the decrease in metabolic rate, what they used to eat prior to dieting can increase weight even more than before dieting (Baechle and Westcott 2010). On the other hand a sensible, balanced diet combined with resistance training can result in an increase in muscle mass which can offset the slowed down metabolic rate from decreased calorie intake. Baechle and Westcott 2010 p 5 summarized the benefits of strength training to metabolic function well: “Strength training appears to have a threefold effect on metabolic function and energy utilization. First, strength training produces a large increase in energy use during the exercise session. Second, strength training results in a moderate increase in metabolism during the postexercise period. Third, the strength-trained muscle requires more energy all day long, which leads to a significant (7 to 8 % as per Campbell et al. 1994; Pratley et al. 1994) increase in resting metabolic rate. Clearly, developing larger and stronger muscles through sensible strength training is an effective means of enhancing metabolism.” This is not to say that cardiovascular training should not be included in a weight loss program: cardio is important both for heart health, overall physical health, mental health and calorie burn. However, resistance training is often overlooked when it really shouldn’t be.
References:
Baechle, T., and Westcott, W. 2010. Fitness Professional’s Guide to Strength Training Older Adults. Champaign, IL: Human Kinetics.
Ballor; D., and Poehlman, E. 1994. Exercise training enhances fat-free mass preservation during diet-induced weight loss: A meta analytic finding. International Journal of Obesity 18:35-40.
Brehm, B., and Keller; B. 1990. Diet and exercise factors that influence weight and fat loss. IDEA Today 8:33-46.
Campbell, W., Crim, M., Young, V., and Evans, W. 1994. Increased energy requirements and changes in body composition with resistance training in older adults. American Journal of Clinical Nutrition 60:167-175.
Evans, W., and Rosenberg, I. 1992. Biomarkers. New York: Simon and Schuster.
Mann, T. Tomiyama, A., Westling, E., Lew, A., Samuels, B., and Chatman, J. 2007. Medicare’s search for effective obesity treatment; diets are not the answer. American Psychologist 62 (3):220-233.
Nelson, M., Fiatarone, M., M., Morganti, C., Trice, I., Greenberg, R., and Evans, W. 1994. Effects of high-intensity strength training on multiple risk factors for osteoporotic fractures. Journal of the American Medical Association 272(24): 1909-1914.
Pratley R., Nicklas, B., Rubin, M., Miller, J., Smith, A., Smith, M., Hurley, B., and Goldberg, A. 1994. Strength training increases resting metabolic rate and norepinephrine levels in healthy 50- to 65-year-old men. Journal of Applied Physiology 76:133-137.
