Like Glencampbell said.. electrolytes! Meant that I only ached afterwards… but oh I ached then..
I was using 1 and a half nuun tabs in a 2l camelbak, and a 1l bottle on the bike with non electrolyte energy drink. I filled a load of zip-lok bags with bottle sized, strong doses psp22. Was easy peasy when we got to water stations then.
Take plenty of bars, sausage rolls, cheese sarnies etc. Gels with caffeine are awesome when it's getting on a bit! basically a bag full of food won't do you wrong.
3l seemed enough between each water stop and we did it in the summer. If you're a thirsty chap it might be worth taking a spare bottle though.
I went to meet some mates in the pub when I got to Winchester.. 2 pints and I was fast asleep in the corner.