Exercise-induced hypoglycemia: sudden blood sugar drop
IntensityBlood sugar drop below 3.9 mmol/L during prolonged effort, with power loss and hunger sensation.
Exercise-induced hypoglycemia occurs when hepatic glucose production no longer matches muscle demand, typically beyond 90 min of continuous effort if external carb intake is insufficient. Early signs: power drop without external cause, intense hunger, cold sweating, light-headedness. Untreated, it can lead to complete blackout (bonk / marathoner's wall) with inability to continue. On a half-Ironman, it is rare before 3h of effort if the carb strategy is correct (>60 g/h). On a full Ironman, it is the first nutrition risk between 5h and 9h of racing. Immediate treatment: 20-30 g fast carbs + intensity cut 15% for 15-20 min, gradual return to target pace.
In TriPaced:
TriPaced calibrates its long sessions beyond 2h with a nutrition prescription proportional to intensity: at least 60 g carbs/hour beyond 3h, 80 g/h beyond 4h. External glucose becomes the primary fuel after 90 min of racing. The tip 'Nutrition failure in race' details early signals and the aid-station plan B.
Source Jeukendrup AE, 2014: A step towards personalized sports nutrition: carbohydrate intake during exercise, Sports Medicine