You have probably read on various blogs and even in many health and fitness books that building muscle is important (which is true) and that for every pound of muscle you can add you will increase your metabolic rate (again, this is true). Then you continue to read on and what typically follows is …and with each pound of new muscle you add your body will expend an additional 50-75 calories and that fact I’m sorry to tell you is false. We now know, however, that each additional pound of lean muscle tissue actually requires about 6-7 calories per pound per day to maintain while adipose tissue (fat) requires 2 calories/pound/day. I like to think of it this way – a pound of muscle burns three times more calories than a fat pound of fat and muscle has greater density (see photo) and takes up 1/3 less space compared to fat. This is why you look better after months of consistent exercise even if you do not lose much weight (hint: it’s not about body weight; it’s about the ratio of muscle to fat).
You might be asking yourself at this point – is it even worth it to start or continue on with my strength training routine? I’m here to tell you YES IT IS !! Your goal at this point, especially if you’re a baby boomer like me (born between 1946-64) is to increase the amount of muscle that you have. Why? Because you will begin to lose it as you age and as a result your strength will decrease and your functional ability will deteriorate. The name associated with this muscle loss is called Sarcopenia and here is a great book for further reading. As we age we will continue to lose, in the vicinity of, 0.5 lbs to 0.8 lbs. of lean muscle tissue each year after age 40 and possibly even younger. There is some research (Nair, 1995) that shows a muscle loss of 3-5% per decade starting at age 30 for individuals who have been inactive. If you’re in the age range of say 45 to 55 that is about 5-8 pounds of metabolically active muscle tissue that you will no longer have. As you get older the loss becomes even more pronounced and by the time you reach age 70 the muscular system has undergone a 40% loss of muscle mass and a 30% decrease in strength (Rogers & Evans, 1993).
It has been said that the best medicine is prevention. To help prevent the loss of muscle, start or continue with your weekly strength training sessions, you will be glad you did …especially later in life!
Nair, K.S. (1995). Muscle Protein Turnover: Methodological Issues and the Effect of Aging. The Journals of Gerontology 50A:107-114.
Roubenoff, R. (2001). Origins and Clinical Relevance of Sarcopenia. Canadian Journal of Applied Physiology 26(1):78-89.
Porter, M. (2001). The Effects of Strength Training on Sarcopenia. Canadian Journal of Applied Physiology 26(1): 123-141.
Rogers, M. A., & Evans, W. J. (1993). Changes in skeletal muscle with aging: Effects of exercise training. In J. O. Holloszy (Ed), Exercise and Sport Science Reviews. Baltimore: Williams & Wilkins.