The last few years I have personally learned a lot about health and fitness. The hunting experiences that I have been in, made me realize it's importance. The majority of what I want,  and like to hunt, are in places where the access to four wheelers can only take you so far. Packing in and dragging your butt up mountains isn't easy by itself. Then add your bow, packs, climber stand (if needed) and you are exhausted by the time you get to your hunt location.  However, if you prepare for your hunt with exercise it can make all the difference. You will not be shaking and out of breath if you have to draw your bow or look down your sight all of a sudden.

  Water is key! Drink more than usual on days you hunt. And breakfast is important to get you through an entire day in a stand, oatmeal works great!  Bring healthy snacks, granola, almonds etc., plus if you unwrap snacks prior to going into the wood and use cloth bags to keep it in, it's quiet. 
  So when it's off season, try getting ready for your upcoming hunt. It will take months! Just going for a walk everyday can help. I personally like running or some sort of cardio. Sweat for at least 30 minutes a day . Get your heart rate up. Something so simple can help you hike to a location, where the guy eating McDonalds physically can't get to!