Do You Really Need Energy Gels for a Half Marathon?
The half marathon sits on an interesting metabolic boundary. A runner running under 75 minutes will rely almost exclusively on resting muscle and liver glycogen. However, for anyone racing between 1 hour 30 minutes and 2 hours 30 minutes, running at 80–85% of maximum heart rate burns approximately 2.5 to 3.5 grams of carbohydrate every single minute.
Sub-1:30 Finishers
Intense anaerobic threshold running diverts blood away from the stomach. 1 to 2 gels taken at minutes 30 and 60 (or mouth-rinsing carbohydrate drink) provide the central nervous system boost needed to sustain late-race kick without GI stress.
1:45 to 2:30+ Finishers
Time on feet exceeds 100 minutes. Without exogenous carbohydrate replenishment, muscle glycogen drops below critical thresholds around Mile 9 or 10, causing the classic "dead legs" feeling. Taking 45–60g carbs per hour keeps muscle glycogen spared.
The Pre-Race Prime (15 Minutes Before)
Because the race pace is significantly faster than a full marathon, consuming a gel with 150–200ml water 15 minutes before the start horn is one of the most effective strategies. It ensures active circulating blood glucose from the first mile, delaying your liver's need to dump stored glycogen early.