It had to come: the backlash to the nation's running madness, the reaction to the death -- while running -- of Jim Fixx, famed author of "The Complete Book of Running."

At the time of Fixx's death, Dr. Henry Solomon, a New York cardiologist, already had on the presses his cautionary view of the health and medical implications of strenous exertion.

Exercise enthusiasts are likely to disagree with Solomon, who offers the viewpoint of a highly qualified medical skeptic. His theme: People exercise because they have "bought the mistaken idea that strenuous effort promotes health and longevity" when, he says, it does not. While exercise may make you look and feel better, he says, it will not make you healthy. Fitness and health, he declares, are two different qualities, independent of each other.

He is clearly appalled by the size and extent of the "exercise marketplace," which provides everything from medical stress tests to jogging clothes. Stress tests, widely used to check heart function, are, he says, unreliable, of limited value and potentially dangerous.

Running is a particular target of Solomon, who counters claims of improved cardiovascular health. He concedes that some people with mildly elevated blood pressure can be successfully treated through an exercise program, which will reduce their blood pressure and cut their risk of heart attack and stroke. But he adds that controlling such mild blood pressure may not even be necessary, or that medication may be a better treatment.

He is also unimpressed by studies showing that exercise raises blood levels of high density lipoprotein, or HDL, the material that acts to prevent fatty buildup inside coronary blood vessels. The increases are too modest to be important, he contends. Besides, people who choose to exercise m (National Caucus of Labor Committees photo) HDL is of any benefit, anyway.

If he is dubious of the benefits of exercise, Solomon is positive about its dangers. People don't just die in spite of exercise, he says; they die because of it. In addition to the coronary dangers, he says, there are dog bites, thrown objects, injured joints and muscles, and heat strokes.

Lest we think he is opposed to exercise, Solomon concludes by noting, "This is not an antiexercise book." He counsels a cautious approach to exercise, not continuing in activity to the point of exhaustion or chest pain.

His message is that you can't exercise for your health, nor can you run for your life -- but it's okay to exercise for fitness and for pleasure.

The book may save lives if it dissuades some people from reckless activity. On the other hand, if it scares people off their feet and into their armchairs, they will probably be the losers.