If you are already doing another sport or activity, you may consider alternating between this activity and your PPU coursework to make sure your body gets proper rest for each.  Depending on the activity, you may be able to do one in the morning and one in the evening.  Keep checking in with yourself and see if your routine feels balanced.  One effective gauge is to note if you have energy, strength and desire before each session.  If not, assess if you need a different frequency or more rest in between.