My coach scheduled a forty five minute run in Zone 2 for me today. The route that I ran here in Colorado, was perfect for reinforcing the fact that Zone 2 runs are about effort and not about pace.

I ran five miles this afternoon. The first two and half miles were all uphill, at a grade of about 3-5%.  For the second half of the run, I simply turned around and retraced my route back to our condo. 

It was a very challenging route for a Zone 2 run.  Clearly the first half is way more difficult than the second half.  Running constantly uphill for two and half miles is hard, so in order to keep my effort level in Zone 2, I had to run much slower than I typically would for a Zone 2 run.

If you look at the first half of the run in the above photo, you can see that my average pace going up the hill, was significantly slower than the pace coming down.  I know I did a very good job of controlling “effort” however, by comparing my heart rate data for the two halves of the run.

• Uphill :        Average HR = 141 bpm and Peak HR = 154 bpm
• Downhill :   Average HR = 140 bpm and Peak HR = 146 bpm