The Week That Was
Friday: 1.75hr. treadmill run (1.0hr. lower half zone 2; 0.75hr. zone 4, max. 175)
Saturday: 1.0hr. treadmill run (lower half zone 2)
Sunday: 2.75hr. treadmill run (zone 2)
Perhaps Sunday's run gave me a rough guide to what proportion of carbs versus fats I was burning in zone 2. Somewhere over 80 minutes into the run I was feeling glycogen depletion effects, also evident in my decreasing heart rate. I took in a 100 calorie gel at 90 minutes, 110 minutes, 130 minutes, and 150 minutes; for the rest of run glycogen depletion felt less pressing, and my heart rate moved back up appropriately. The treadmill claims I was burning 297 calories per 20 minute segment, and it seems I wasn't burning more than the 100 calories of carbs in the gel.
For me to believe that, though, I have to believe having glycogen depletion kicking in before 90 minutes. Friday evening's run was demanding - gotta love the fast finish long run (although I don't do the final kick at 10K pace). My Sunday breakfast was about 400 calories, and I didn't start running until 3 hours after that was done.
Yeah, it's a stretch. Nice to dream though!