Don't Doubt the Value of Exercise, NHLBI Author Advises
In an editorial published in the Journal of the American Heart Association, Dr. Michael S. Lauer mentions discusses the meaning of a study in the same issue urging higher doses of aerobic exercise for low-risk adults.
The current U.S. guidelines recommend that most adults get moderate exercise for more than 30 minutes per day, five days per week. The authors of a study published in the August issue of the Journal of the American Heart Association recommend prescribing even higher amounts of exercise to low-risk adults because they conclude lower fitness raises the risk of cardiovascular disease and death.
Dr. Michael S. Lauer, MD, FAHA, who works in the Division of Cardiovascular Sciences of the National Heart, Lung, and Blood Institute at NIH, praises the study in an editorial included in the issue. He cites a few ongoing controversies about health, including doubt cast on the value of annual physical exams and the government’s guideline for reduced salt consumption.
"Some of us worry that that people might misinterpret public health recommendations to mean that anything less than 150 minutes of exercise per week is of no value and therefore not worth pursuing at all. To add to the confusion, we now are aware of data suggesting that some adults might be harmed by exercise," Lauer writes. "It is critically important to avoid oversimplifications that overlook nuanced quantitative and qualitative issues: Just as not all fats are the same and not all carbohydrates are the same, not all exercise, whether of short or long duration, is equivalent either."
He observes that the evidence we have at this point isn't ideal, but still it supports the value of exercise. "On the basis of what we know to date, exercise can be an extraordinarily powerful preventive intervention, an intervention that might prevent premature death, myocardial infarction, stroke, cancer, depression, dementia, and disability. Nevertheless, in contrast to the situation with blood pressure and cholesterol treatment, there is remarkably little randomized trial evidence supporting routine exercise prescription. Perhaps this is because it is much more difficult to prescribe an exercise regimen to which people will adhere than it is to prescribe pills. So far, trials have focused either on surrogate measures or on special populations, like those with heart failure or glucose intolerance."
Public health research on the effects of public policies on levels of physical activity would be helpful, he writes, giving installation of pavements and increased numbers of neighborhood recreational facilities as potential examples.