water

Living in London the hot weather is starting to take its toll on me. I am not complaining but in the tube its just so ridiculously hot, and busy.
so what I ensure I have is a really cold big 2 litre bottle of water that I carry with me.
Its so important because we loose water so quickly through sweat unfortunately ( because of being in that horrible tube)
so I make sure that I replenish by carrying that bottle of water with me