A couple of things inspire me to exercise. 1) stress relief and meditation -I find both running and swimming a quick and reliable way to de-stress and also to meditate (listening to breathing and footfall/stroke patterns is very rythmic). 2) My sister has a lot of serious health issues that stop her from doing a lot of things. So I sort of feel like "I'm here, healthy and can do it - so I should!!". 3) I am a bit of a rock climbing junkie. And as you progress through the grades it becomes apparent how important some cardiovascular fitness is (+ walking up steep tracks to get to some areas can make you more tired than the actual climbing). So on top of training for rock climbing, I run and swim for fitness.