Go ahead, give yourself a day off

For those who fear the wrath of their personal trainer, here’s a gentle message: Exercisers who favor moderate to high intensities should take one day of rest a week to allow the body to rejuvenate and consolidate the gains of exercise.

Exercise causes micro-trauma to muscles, which get stronger when they repair themselves during rest. The same applies to your general physiology, which must “ramp up to meet the demands of exercise,” says Conrad Earnest, chief exercise physiologist at the Cooper Institute in Dallas. He and others recommend one full day off a week.

Without proper recovery time, areas of wear and tear become weak links and are more prone to injury and, importantly, less likely to show strength gains. While you might burn a few extra calories by not taking a day off, your body will be less efficient in capitalizing on the work you do.

In most cases, you’ll only become cognizant of this accumulated stress if you exercise at a relatively high level. For example, maybe one day you can’t beat a regular foe to the hoop like you did a couple weeks ago. Or you bonk on a big hill climb that you recently handled with vigor.

Don’t wait until you feel pain or weakness to rest, says Dr. William Roberts, an associate professor in the Division of Sports Medicine at the University of Minnesota. But do “rest more if you have symptoms,” he says. Skipping rest days, he asserts, is the most common cause of overtraining injuries.

Even if you don’t feel the sluggishness, the off day should affect you like a long weekend break from a high-pressure job: You’ll return to the gym, pool, track or trail notably more refreshed than when you left.

For someone who jogs regularly, rest could mean a light swim. For a devoted weight lifter, it could be a casual bike ride or noncompetitive tennis game.

Earnest and Roberts agree that a rest day is not needed for low-intensity exercisers, such as people who walk a couple miles a day simply to clear their head and get a little blood flowing.

But for those who train hard, trainers urge “periodization” -- variation in the amount and intensity of exercise -- and some volume of rest, regardless of your training cycles. For those devoted to what is called the “macro-cycle” of year-round sports training, Roberts recommends taking a month of rest per year. For people in a “meso-cycle” of three to six months of training, he recommends one week off.

Those breaks from the grind -- including that all-important day-off-per-week for those not in serious training -- maximize gains while reducing risks.