The days of being able to spend all day just training are over, due to the responsibilities of travel, work, and family. Here’s the good news: New research suggests that you can burn more calories in the gym with shorter, more intense workouts versus longer workouts.

Dorian Yates once said, “The most common misconception that people have is that I spend all day in the gym. I normally spend 45 minutes to an hour working out.”

Researchers took trained men and had them perform a traditional workout doing four sets of eight diferent exercises (bench press, leg press, leg curl, seated row, military press, biceps curl, triceps extension, and situp). A second group performed high-intensity training, using heavier weights and lower reps. The high-intensity workout was much shorter. The traditional workout took 52 minutes to complete, whereas the high-intensity workout took 22 minutes. They measured the men’s metabolic rate on two separate occasions, once before the workout and then again 22 hours after it was finished. At the end of the study, training volume was much higher for the traditional resistance-training group (17,273 pounds vs. 8,536 pounds).

When metabolic rate was measured 22 hours afer traditional training, resting energy expenditure was about 100 calories higher than normal, whereas resting metabolism rose by more than 450 calories in the high-intensity training group. Furthermore, high-intensity training increased the rate at which fat was being oxidized to a greater extent than traditional training.

The greater post-exercise muscle damage that occurred during high-intensity training resulted in greater energy expenditure for muscle tissue repair and protein synthesis that could contribute to greater metabolic energy expenditure after training.