5:10 → 5:35
Skipped the second gel.
At my sub 1:50 attempt, I skipped my second gel because I "felt fine". By km 16, my pace dropped from 5:10 to 5:35. I never recovered.
BUILT BY A SUB-1:50 FINISHER
When to take energy gels during your sub 1:50 half marathon. Based on real race-day data from the 15K wall mistake.
Your race-day plan
Real experience
The mistake that cost me 25 seconds per kilometer.
At my sub 1:50 attempt, I skipped my second gel because I "felt fine". By km 16, my pace dropped from 5:10 to 5:35. I never recovered.
Don't wait until you're hungry or tired. By the time you feel it, your glycogen is already depleted. Take gels before you need them.
Your body needs roughly 60-80g of carbs during a 1:50 effort. Two well-timed gels (25g each) at km 8-9 and km 14-15 covers this without overwhelming your stomach.
The toolkit
Calculate your exact splits per km / mile.
12-week fragmented-time plan for busy runners.
Convert outdoor pace to treadmill speed + incline.
Train by effort using Karvonen or Fox formula.