I went for a ride up to Nant today, the first descent that I did was Zorro and it felt pretty terrible. Balance was off and not feeling it. At the bottom I was feeling quite dehydrated though so I drank all of my water which meant that I needed to refill from the stream. I realised that I'd never actually been down to the stream and looked down the tunnel, so that is what I did. By the top of the leg burner I was feeling much better and had a great ride for the remainder! I've kind of known for a while that being dehydrated seems to exacerbate things and this just reinforced that. Fine line though, drink too much and I'll stopping every few minutes for a wee!