Re-examining the Value of Aerobic Exercise: Part II

by Charles I. Staley, B.Sc., MSS
(Posted 10/5/96)

Recently, I questioned the obsession most Americans have with aerobic exercise- particularly when done for the purpose of improving physical appearance (which, of course, is why 99.5% of all people exercise in the first place). This article prompted several letters and phone calls, most of which were critical. Therefore, I'd like to clarify my position in this month's article

Obviously, compared to a sedentary lifestyle, aerobic exercise is quite beneficial. The people I'm trying to reach with this message are those individuals who are not competitive aerobic athletes, but who nevertheless spend between 5 and 10 hours a week in the aerobic zone, for the purpose of improving their appearance. These individuals (and there are legions of them) would benefit by reducing their volume of aerobic exercise, and incorporating resistance training into their program.

Even aerobics instructors have intuitively known this for quite some time. Every time I walk past an "aerobics" class in a health club, or if I happen upon one on TV, they're lifting weights. Small ones, of course- they need to guard against gaining too much muscle. Funny how most men have a tremendously difficult time gaining muscle, despite grueling weight lifting programs, while women claim that they grow like weeds just thinking about lifting! Why is this?

One of my "detractors' wrote that (I paraphrase) beginners can benefit from 30 minutes of brisk walking, for which they need no instruction. I couldn't agree more. But walking is a VERY beginning form of exercise. In fact, I consider walking a form of locomotion, not exercise. When the simplest of life's requirements, such as walking, climbing stairs, and carrying groceries are exercise, I'd say you're in pathetic (perhaps pathologic) shape. In this case, walking is in fact an ideal form of exercise. Once you get beyond this point, however, more strenuous forms of activity should be explored, in order to respect the principle of progressive overload (i.e., "If you keep doing what you've always done, you'll keep getting what you've always gotten.")

Resistance training does have a few down-sides, depending on your perspective. It does require a certain amount of supervision, at least in the beginning. And of course, it demands hard, physical work, which most people disdain. Infomercial companies know this well- selling their exercise gimmicks with phrases like "You can do it while you watch TV," and "It only takes 10 minutes a day!"

Regardless of what your exercise regime consists of, your success will largely depend upon the degree to which you really enjoy exercising. You do best what you do most, and you do most what you enjoy doing. How many times have you heard this exchange in your health club?: "Hey Bob- how's it 'goin?" "Well, it'll be goin better when I get outta here!" In my experience, Bob is very unlikely to make progress, unless he can find a way to enjoy and appreciate physical activity.

What the Research Literature Has to Say About Strength Versus Aerobic Exercise

From Pollack, in the Southern Medical Journal, Volume 87, No. 5, 588· Low levels of aerobics yield the same health benefits as higher levels· Master runners show a 2kg. average LBM loss· Higher intensity resistive training may be necessary for a large percentage of the healthy elderly population.

From Ketelhut, in American Heart Journal, 127 (3): 567-71, March, 1994 "We conclude that the gradual decrease in arterial pressure seen with prolonged aerobic exercise (60 min.) is the result of a fall in cardiac pump function (as measured by cardiac output, ejection fraction, fractional fiber shortenings and contractility index), possibly indicating cardiac fatigue."

From Todd, in Sports Medicine, 14(4): 243-59, October, 1992  Circuit weight training has been shown to improve aerobic endurance and muscle strength and to have additional benefits of improved treadmill time compared with traditional aerobics programs.

From Boyden, in Archives of Internal Medicine, 153(1):97-100, January 11, 1993· In healthy pre-menopausal women with normal baseline lipids, 5 months of resistive exercise training reduced) total CHO and the LDL fraction.

From Campbell, in American Journal of Clinical Nutrition, 60(2): 167-175, August, 1994· Resistance training is an effective way to increase energy requirements, decrease body fat mass, and maintain metabolically active tissue mass in healthy older people and may be useful in weight control.

From McCartney, et al:, in American Journal of Cardiology, May, 1991· There is a much better adaptation to life activity with weight training.

From Thomas, in Southern medical Journal, Vol. 87, No. 5· "Because of the correlation between bone mass and muscle mass, an increase in muscle mass is a desired effect of exercise."