What’s it take for healthy overweight inactive men to get into shape? Not much, according to research from the Norwegian University of Science and Technology. A 10-week study with a group of 13 subjects showed a 10% increase in maximal oxygen uptake could be achieved with just 4 minutes of intense exercise at 90% of maximal heart rate performed 3 times each week.

Some of these subjects undertook a 4×4 training protocol involving 4 minutes of high intensity exercise at 90% of max heart rate followed by 3 minutes of active recovery at 70% max heart rate. Completing 4 intervals 3 times a week increased maximal oxygen consumption – an established measurement of fitness – by 13%.

True Strength Moment: Despite the promise of fast, easy gains with 12 minutes of training each week, the subjects who worked the slightly more difficult 4×4 program realized better results. These training programs are fine for people with little to no experience working out, but probably aren’t adequate for those dedicated to an active lifestyle.