In my experience the risk of hypos is greatly reduced by eating a diet very rich in fat and poor in CHO. If you "teach" your body to burn fat rather than sugar you won't experience those nasty BG ups and downs so typical when you eat carbs and exercise a lot.
Back when I was eating carbs, I used to eat jam, bread or biscuits before running and after each hour I had to eat sugar or else my BG would drop. Now I usually exercise on an empty stomach and my BG would be nice and steady for all the duration of the run or whatever it is that I do.
Obviously I still get the odd hypo, so in my backpack there's always some sugar just in case, but normally if I plan to run for more than two hours I prepare me a concoction of almonds, coconut oil, dark chocolate powder, dried coconut and heavy cream, or some pemmican, which I share with my dog when one uf us two gets hungry...