I've been getting headaches usually a few hours after my runs, especially now I'm doing longer runs (just finished week 7).
It's not because of dehydration, or lack of/too much food before/after running but on doing some research yesterday I came across a possible answer, which could be low sodium and therefore an electrolyte imbalance. Further research led me to thinking that drinking an isotonic drink such as Lucozade Sport after the run would rebalance me.
So, I'm going to try this on my next run on Monday and I will report back. But in the meantime can anyone shed light on isotonic drinks - do they work?