The American College of Sports Medicine (ACSM) in their fourth edition of Guidelines for Exercise Testing and Prescription (1991) set the tone for a new approach toward exercise prescription for cardiovascular fitness.

Prior to this edition, fitness professionals were guided by the philosophy of 20 to 30 minutes of continuous activity at 60% to 85% of maximum heart rate (MHR) three times a week, as the foundation for prescribing exercise. Anything less than this 60% of MHR was considered ineffective for cardiovascular improvement, and often the cardiac risk factor assessment of the individual prohibited prescription of this type of activity without extensive medical evaluation and supervision.

The ACSM 1991 revisions opened the door to a new world of exercise prescription by suggesting that "exercise in moderate amounts and at moderate intensities, is more beneficial to health than previously thought; most adult Americans are either sedentary or participate irregularly in exercise and, therefore, for a large fraction of the population adoption of a regular, moderate exercise program is probably a more realistic goal than is adoption of a vigorous program; and exercise, particularly moderate exercise, is quite safe and consequently expensive medical evaluation is not needed by the vast majority of persons who plan to start a moderate exercise program." Here "moderate" is defined as 40-60% of MHR. These revisions have led to the sanctioning and encouragement of participation in moderate exercise programs by most professional fitness organizations.

In the past year much attention has been given to "Exercise Lite," and other derivatives of this more moderate approach. In fact, in February of 1995, the Centers for Disease Control and Prevention and the American College of Sports Medicine issued a new less stringent recommendation for health: "Every American should accumulate 30 minutes or more of moderate intensity physical activity on most, preferably all days of the week."

To the lay person the debate about quantity and intensity continues and the questions become:

Q: Does the past standard expect too much?

Q: Does the new encourage too little?

Q: Are we sending mixed messages to the public?

And the answers appear to be yes, yes, and yes!

Further examination of several issues relating to this topic, however, can hopefully shed some light on the debate, and help fitness professionals communicate a clear message to their clients.

In 1992, the American Heart Association identified an inactive lifestyle as a major contributing risk factor for cardiovascular disease. Inactivity now joins the ranks of obesity, hypertension, hyperlipidemia and smoking, as an independent cardiovascular disease risk factor. This fact in itself should make a good case with fitness professionals for encouraging activity among their clients.

First, let us consider the issue of moderate intensity activity. There has been a lack of consistency in past research with regard to the definition of moderate intensity. It is clear now that researchers agree that more than 60% is more than moderate. Practically speaking, brisk walking, climbing stairs, gardening, playing with children, and house-cleaning may meet the level of moderate activity. It is also clear now that there are clearly documented positive effects of moderate intensity exercise, which include lowered blood pressure, improved lipid levels, improved glucose uptake, control of body composition and improved blood clotting factors.

The more important issue regarding moderate intensity, is

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that there is less risk of injury, less incidence of heart attack during or immediately following exercise, and it is an attainable goal of the deconditioned population. Encouraging moderate activity involves less risk to the fitness professional since it requires less prior screening, evaluation and supervision of the individual client.

Another change in the approach toward activity includes the issue of multiple bouts of short duration on most days of the week, versus a continuous bout three times a week. Once again, research is beginning to support the fact that multiple bouts have approximately the same accumulative effects as a longer single bout. Adherence seems to be better with deconditioned participants, if they are allowed to perform multiple bouts, as opposed to one longer bout of exercise. And finally, many of the deconditioned population could not attain the goal of a longer bout in initial attempts at being active. The flexibility to do three 10 minutes bouts of exercise allows this population a chance to be successful.

Another issue considered to be significant to being active for health benefits is the consistency of exercise. Exercise sessions that occur less than two times per week do not appear to be effective, and indeed could be dangerous to the deconditioned population. The current recommendation encourages daily moderate activity.

Some professionals suggest looking at the issue of "how much is enough" from the standpoint of calorie burning.

It is suggested that every American should burn off 1,500 calories per week doing some type of moderate activity each day. This again puts activity in another light. Those who run three miles at a faster pace, will burn off 300 calories (approximately) in less time than those who walk 20 minute miles and also burn off 300 calories (approximately). This 200 to 300 calories burned on most days of the week would add up to the 1,500 considered beneficial to health, and it does not appear that it matters whether these calories are burned off in moderate or vigorous activity!

The American Heart Association has indicated that the new approach toward exercise is designed to reduce the risk of cardiovascular disease. The Centers for Disease Control and Prevention and the ACSM indicate that this change is aimed at improving overall health of a sedentary population. The ACSM wishes to recognize the role of exercise in the prevention and management of hypertension, hyperlipidemia, weight control, and the prevention of osteoporosis.

The issue becomes one of purism versus holism with regard to fitness. True cardiovascular health benefits can be achieved via the more moderate approach, yet cardiovascular improvements of a more definable nature require more specificity and vigorous activity. This is an issue of general health enhancement versus cardiovascular fitness. It becomes an issue of the general population versus the athlete.

There is not an argument against the more vigorous types of activity previously considered necessary for fitness gains, but a recognition of the fact that less is okay, and in fact may be all that we should expect. Though some is better than none, we will not deny that more may be better than some. Research does indicate that the value of exercise does not increase incrementally with the amount, however. Indeed too much may have adverse effects on health.

The implications of this more holistic approach towards exercise are dynamic. More people will feel that they can "do it!" We will see the improvement of cardiovascular health of the general population. We will begin to see exercise as medicine (Ex is Rx)!

Physicians will begin to prescribe exercise with less reluctance and concern about risk involved. We can take exercise out of the "club" setting to where we live and interact in the community. We will see a call for public action, see walking clubs and other forms of activity made available at the grass roots level, without the need for costly club memberships. It will be easier for the fitness professional, not to be confined to the strict number guidelines, but free to consider the individual, where he/she is and what his/her goals are.

Though facing more of a challenge, the fitness professional can now be more creative. Now the answer to "what is the best exercise?" becomes that which you can and will do consistently!

In summary, we must accept and conclude that any exercise is better than none, and depending on the goal of the participant, it might be just the right amount as well!

Elaine J. Layden has a MA. in Exercise Physiology. She is the director of the Village of Lyons, senior/activity coordinator for the Westchester Park District, and an independent contractor in the area of health and fitness. She has also been a commissioner for the Community Park District of LaGrange for the past 10 years.

Q&A from the University of California at Berkeley Wellness Letter

What are the effects of exercise on energy levels? If you're tired, will exercise make matters worse, or will it perk you up?

It depends on your physical and emotional state, of course, and on what kind of exercise you do and how much. If you're tired because you're sick (from a cold, flu, or more serious ailment such as anemia or a hormonal disorder), seriously sleep-deprived, or malnourished, exercise probably won't help much. But if your fatigue has no underlying medical cause or comes from anxiety or mild depression, exercise may give you a boost. Moderate aerobic exercise such as running or swimming tends to be most effective.

In addition, being tired may actually be caused, at least in part, by a lack of exercise—what the experts call "sedentary inertia" or "exercise deficiency"—in which case exercise is the best antidote. But you need to do the right amount of exercise; over-exercising can leave you exhausted.

The University of California at Berkeley Wellness Letter is a monthly newsletter of nutrition, fitness and stress management, published by Health Letter Associates, P.O. Box 412, Prince Street Station, New York, NY 10012-0007.

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