I like to run. I used to run about 15km 3-5 a week in grad school. A daily run each afternoon is how I fondly remember it, especially when the work was hard/focused. These days I run 5km twice a week on my cardio days, and daily when I’m on holiday somewhere tropical. My knees hurt, I use a treadmill instead of the footpath now mostly, but I still look forward to my runs.