Exercising with periods of high intensity and alternating them with periods of low intensity keeps me burning calories far after I've stopped working out.
Intervals can speed up weight loss. It has mine!
I walk at 3 mph for 5 min, then run at 6 mph for 1 min. I alternate that over 20 minutes. Then I cool down by walking at 3 mph for 2 minutes, then 2 mph for 2 min, then 1 mph for 1 min.