Run Uphill
That’s it: Find a steep hill in your area, or set a treadmill to an incline (try to start around 4-5 degrees in the beginning), and run really hard until you reach the top or a couple of minutes pass. The great part about doing this out in the real world is that the time it takes you to walk or jog back to your starting place should be perfect for your cooldown period, and then you’re ready to do it again. Again, several reps here is a good goal for first-timers, but you’ll want to push to something like 10.