Depending on how you want to hunt, or shoot, maintaining fitness is a huge deal. I take my fitness fairly seriously, but I'm hardly a gym junkie/bodybuilder type.
When I first started really getting into hunting, I got access to some crazy rough country here in Australia. Steep, rocky, etc. I was in my early 20's but a my university years of drinking too much and eating a lot of bad food saw me get reasonably unfit. I always thought fitness was easy until I stopped playing regular sport, and this became painfully obvious when I tried to hunt my favourite spots and could barely walk out of them. I know it might sound silly to older people that a 23 year old wasn't fit enough, but it's true.
Since then, I started learning a lot more about hunting and fitness on youtube and really got into blokes like Cameron Hanes and Remi Warren, who are in great shape and stay that way either by hunting regularly, or training regularly so they can continue to hunt as best they can. I liked that idea.
I started playing touch football regularly in order to build stamina and speed, and lifting weights regularly as well. Strength is always a good thing - whether it be for carrying a heavy load on your back, having good legs to push you up a mountain, throw around a dead animal easily when butchering, or being able to draw a bow.
I've gone through fluctuations of working out over the last few years, and a lot of it has to do with the hours I've worked and the limited gym options available in a very small town where I lived. I'd find the time for a few months and then something would change in my lifestyle and all of a sudden I couldn't get to the gym enough to justify a membership, so playing touch footy took over. Now I live in a bigger town I've been going to the gym regularly and it's doing me wonders.
The blokes in the gym are hunter friendly and put me on a program that will help with building strength in important areas for hunting. Lots of deadlifts, squats, and rows, among other things that either build my chest up a little bit, or assist with range of motion and mobility. I have to say, the back and row type exercises really seem to help with drawing a bow.
I recently broke my compound bow and the only recurve I have at the moment is a 65lb BW. I got it a week ago. I consider myself a fairly strong bloke and I'm only 31 years old, but this bow is very difficult to draw back. Besides working a lot more on my fitness and strength, I am going to buy a lighter bow.
So in short, I personally go to the gym a lot and lift weights, as well as regularly hike/hunt, in order to keep fit. I'm just lucky that here in Australia I get to hunt 365 days a year with no closed seasons or bag limits hindering my opportunities, so my favourite thing to do to keep fit is just hunt.
I figure it'll be easier to maintain fitness into my later years, than it would be to let it go and then try to get it all back in my 40's.