There is a certain macho appeal to bundling up and getting a run in on a cold January morning, but I draw the line sometimes. I mean, 31 degrees isn't too bad, but match it up with 20 mph breezes and you've got tough conditions. And since my gym is only 5 minutes away...
So this morning's 8 mile run was indoors. Since I had some HR zone training to do, it actually worked out pretty well. I did 15 minutes easy on the track, then hopped on a treadmill to do 5 repeats of 4 min Z3, 4 min Z1. Getting to Z3 was easy -- just increase the incline and watch your HR go up. I'd start each Z3 repeat at 5.5%, 9 min/mile, and decrease the incline as I started to hit Z4. For the Z1 segments, I'd slow a bit, and drop the incline to 1% until my HR came down. Gradually speed up the treadmill, then up the incline for the next repeat. Worked pretty well.
After the treadmill, back onto the track for an easy 15 minutes. Good workout, and I didn't even need to put on chapstick.