TIME AND money, when they’re short, tend to translate into fat and decay. So for these hard times, fitness experts Brett Klika and Chris Jordan distilled decades of research about what’s called high-intensity circuit training into a seven-minute workout. Because it uses no equipment, only your body weight, the wall, and a chair, it’s especially attractive for those who don’t want to spend on a gym. And, yes, it is effective. (How do I know? I’ve been doing it for a week, and if pain is a measure of progress, then my agony is ecstasy. I’ve also shed a couple of pounds.) When The New York Times picked up on the authors’ paper in the American College of Sports Medicine’s Health and Fitness Journal earlier this month, the workout went viral. There are 12 exercises of 30 seconds each with 10 seconds in between: jumping jacks, wall sit, push-ups, crunches, chair steps, squats, dips, plank, running in place, lunges, push-ups plus rotation, and side planks. (I ache just writing this.) But that’s only one version, and Klika and Jordan say you can also repeat the routine two or three times in a row. Fortunately, I don’t have that much time.