A Vote Against Aerobic Exercise?

My inbox has been filling up with PR pitches on the ineffectiveness and/or evils of steady aerobic exercise, which most academic fitness experts have preached as the best way to control weight and improve heart health. (I've written about one specific no-cardio plan before.)

I'm tempted to dismiss most of these pitches as gimmicks to sell more books, DVDs, vats of protein powder, or whatever, but there are enough studies cited as supporting evidence to make it a topic worth looking into. Some of the arguments offered up against lots of steady aerobic exercise: Working out for a long time can cause impact injuries and possibly promote harmful bodywide inflammation; people tend to overeat after cardio workouts because they overestimate how many calories they've burned; weightlifting may boost your metabolism more than aerobic exercise in the period after you've finished working out; and—the one that makes intuitively the most sense to me—it's more efficient to do interval training (alternating shorter periods of intense exertion followed by recovery), because you burn more calories in less time.

I'm going to investigate these arguments, as well as any others you send me at onfitness@usnews.com. Please send me your personal stories, too, if steady aerobic exercise has helped or hurt you in losing excess baggage or maintaining your current weight.

Survey: What do you think?