Looking for a simple form of exercise that delivers results? Harvard Health suggests you try interval walking. Interval training is “any form of exercise in which you purposely speed up or slow down at regular intervals throughout the session” — basically, you walk at a regular pace, speed up for an extended burst, and then return to your regular pace and repeat the cycle. Interval training has proven to be remarkably effective, delivering the same benefits that longer regular workouts do, but in a much shorter amount of time.

You can do interval walking outdoors or on a treadmill, and you don’t need much more than a watch or some other timer (your smartphone probably has one) to track your bursts of speed. For more information, you can read the Harvard Health post as a PDF.