I train at a 11.5 mile loop and I do laps about 1hr 6minutes fast and 1h 16minutes when slow. I average HR here would be around 147-150+. The course is mixed with hills, downhill and flat. Didn't monitor my HR on XC Race yet. I would expect a average heart rate between 147- 150's. If I push myself to the limit for 20mins on a gradual climb, then I probably get that average HR higher than 147.
I just remembered starting a ride climbing a steep hill for 0.5 miles and other one for 0.7 miles. My average HR with this ride was definitly in the 150's
I just didn't time trial myself again to push my average HR higher. Anyway, @135-141 Zone 3 in the chart for a 147 average HR is a comfortable pace. What Zone should I use for the 50mile race? Also, any hill climb for me will surely hit Zone 5 in seconds.
Thanks
Dazs