It's paramount. At 42 I have a 2.5 yoa little girl so I'm always on my feet. With that being said, I take staying in shape very seriously. I hike the mountains, run, row, lift weights, etc. I can still run a mile in sub 7 minutes. But I also have a beat up body of many years or sports, dirt bikes, injuries, etc.
I cover many miles in the spring between a couple of states, and usually drop about 5-8 lbs.
I have to say though, more importantly than turkey hunting is the ability to drag a deer a long way on public land. I killed a large bodied buck three years ago on public land in Pennsylvania. My drag was 1.5 miles up a mountain. I had no other choice to get it to the truck before dark. It absolutely destroyed me but I did it. With that being said, it's a year-round thing and a lifestyle for me.