It's amazing how little exercise it takes to do the trick. Personally I feel like it's important to do something that opens the lungs and gets the heart beating

It's amazing how little exercise it takes to do the trick. Personally I feel like it's important to do something that opens the lungs and gets the heart beating, so cardio of some sort is what I choose (sometimes skipping rope). But some sort of all-body stretching (yoga sun salutation or similar) is actually enough.