New research suggests that intensity is best for torching calories during your workout—and for more than 14 hours post-exercise.

Like most of us, you probably work out to help you lose weight and firm up. Unfortunately, our wimpy exercise these days just isn't cutting it, says David C. Neiman, DrPh, who is the director of Appalachian State University's Human Performance Lab, and one of the study's authors. “We need to be pushed again to get lean with exercise. A 45-minute vigorous workout can help you get three times the net calories burned compared to the same 45 minutes spent walking.”

The study, published in the September 2011 issue of Medicine & Science in Sports & Exercise, used a metabolic chamber (considered the most accurate way of measuring energy expenditure) and included 10 male subjects. On the test day, subjects exercised vigorously in the morning for 45 minutes and then measured their metabolic rates for the next 24 hours. The subjects also completed a 24-hour period in the metabolic chamber with no exercise, so that the researchers could compare the differences in energy expenditure between the day in which subjects exercised versus when they were sedentary.


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The researchers found that the men burned some 519 calories during the 45-minute exercise session and then burned another 190 calories in the next 14 hours. They calculated that the exercise session plus the post-exercise increases in metabolism burned a total of 750 calories. If you walked or did another low-intensity exercise for 45 minutes you would burn less than 300 calories and experience little—if any—post-exercise increases in metabolic rate.

If you think you’re too out of shape for this type of workout, think again. “We found that even the subjects who were overweight and out of shape reaped the same benefits, and unless your doctor says you cannot do vigorous exercise, this is something most people can do and can have a big impact on their weight,” adds Neiman.

Bottom line: It takes some sweat equity to get fit and lean. Choose a type of exercise (i.e. running, cycling, swimming) that you like where you can really push yourself so you’re sweating and it’s impossible to carry on a conversation. Great options are boot-camp style workouts, Crossfit, or a hard spin class. Not only will you burn lots of calories during this intense session, it’s likely that it will boost your metabolism for at least the next 14 hours.