Thursday I rode to work. This came hot on the heels of a blood donation, and I actually felt pretty good for the ride to and from work, although I noticed my heart rate sure spiked quickly on the hills. I have my HRM set to beep when I crest 170 bpm. A few times on the way to work I reached 170, and on the way home I hit it quite a few since I took a hillier route home (I had to stop at the bike shop to pick up my new leg armour).