I've always enjoyed leisure walks and rambling in the countryside, it's something my parents used to do a lot with my sister and I when we were young and we've continued doing it of our own accord, into adulthood.
I've cycled 8-15 miles every morning for about 6 months, most mornings for the past year and a half and as often as I've had time and the weather has allowed it over the past 10ish years. I'm really disappointed when I wake up and it's raining heavily or there's high winds outside, especially if it doesn't abate at all later in the day. Generally I wake up, eat breakfast, then cycle before I bathe/shower and focus on productive things for most of the rest of the day.
I took up running for about 6 months but stopped because it was ruining one of my knees, to the point I couldn't walk some days. But running was addictive - the sense of having triumphed over that little nagging voice of doubt in the back of my head saying "you won't make it to the end of this route, you might as well give up" and also the endorphin high. Plus there's the sense of progress when I'd run my route 15-20 seconds faster each time and get my average mile down to around 5 minutes. I think men generally have some kind of primal desire to push ourselves to find out what we're capable of and where our limits are.
Exercise lowers stress levels and also helps me to focus/concentrate better, which is good for my studies during the academic year and recently has been good for sorting out my CV, building a portfolio of coding work and completing applications for industrial placements.