Which do you prefer? Personally I like running outside on a track because I am a sprinter. A lot of people prefer going to the gym rather than running outside. I know here in Canada it is quite cold but it is nice to get fresh air every once in a while.
As a sprinter myself, I hate running on treadmills. I mean they're good for losing weight and all, but for performance you need to run on real terrain.
Running outside is definitely harder for me but I prefer it over running inside on a treadmill. Getting that fresh air and actually seeing your environment while running is much better then just staring forward at a wall for however long you decide to run. 😛
I prefer running outside because, as you said, it's nice to get some fresh air every once in a while. Though I think we must avoid smokey places as it is bad for the lungs. 🙂 Cheers!
