Managing electrolytes during a marathon after cramping from overdrinking sports drink
I'm training for my second marathon and I'm trying to figure out an electrolyte strategy.
During my 30 km long runs, I carry 500 ml of water with only 1/4 of a SIS electrolyte tablet and refill water every 7 km. This has worked well for me, and I don't cramp despite sweating heavily.
In my first marathon, I drank electrolyte drink at nearly every aid station and eventually developed severe leg cramps. It felt like I took in far more sodium than I was used to during training.
Since I can't carry enough electrolyte drink for an entire marathon, I'm wondering how experienced runners manage this. Do you rely on aid stations, electrolyte capsules, chewables, or mostly plain water if you're already taking carbohydrate gels?
I'd be interested to hear what has worked for others with similar experiences.