Exercises are performed in all sorts of ways. Expose your body to more work that it is used to handling, allow rest and recovery and the body will make a positive adaptation as a form of self protection. You can put in more time – do more reps, do more sets, run a little further, engage in whatever the activity is a little longer – and as long as you don’t overdo it the body will come back improved.
You can work a little harder – more weight on the bar, a steeper hill at the same pace, sprinting instead of jogging - and again as long as you don’t overdo it the body will come back improved. If you exercise in this way the workouts cannot be very long but they can be very effective. Just one benefit is fat loss.
From this study, High-Intensity Intermittent Exercise and Fat Loss this quote: