I agree 2 litres of water does little harm to the average paper pusher. The kidney does it's job just fine retaining salt and removing excess water in our body For high perspiring sportsmen such as badminton in tropical climates on a sunny afternoon I would have to differ water to favour a warm bowl of chicken soup, bone soup or something else granny can cook up. Here's a point to ponder. If we start out with 20litres (random figure) in our body and perspire and exhale out 1 litre in the next hour of badminton with no fluid intake does that leave us with 19litres of water in our body? No urination took place in that one hour.
Urine still gets produced but at much lower quantity, due to stress hormones and vasopressin that is produced in strenuous exercise to support blood flow, perfusion, and pressure. Because of vasopressin, less water is filtered and more water is reabsorbed by the kidneys. That's why in the article it explains why that can lead to hyponatremia and water overload leading to brain edema and death in cases of sudden excessive water ingestion post strenuous exercise, eg marathon runners.
If there is an original reference for 8 glasses of water to exercise, then I would think it's extrapolation, not being careful with facts and misquotation. Happens all the time. For the fluid loss, it's not 1litre of sweat. There's also water lost during respiration - with higher frequency of breathing and more air being moved during exercise, this is going to be more. The kidneys don't stop producing urine completely - it's kept in the bladder. There is also water generation from metabolism of energy stores in the body. So, fluid status is not that easy to breakdown into the components without some very sophisticated measurement devices. I agree in the tropics you have to have a different strategy - chicken soup sounds good. Chicken rice even better! I once had nasi lemak and then did the badminton for 3hrs - no air conditioning. Also drank 3litre of 100plus during the session. I had cramps near the end and also bad stomach pains. After 30-40mins recovery and shower, went for night food at hawker centre. Salty Chinese food makes for a great recovery. I felt normal after the meal. It made me wonder if I had got a bit water intoxicated as 100plus is pretty dilute.
I wonder what Lee Chong Wei was drinking when he had the finals of the World Championship 2013. If it was very hypotonic, I can imagine it could cause cramp.
Seriously? Were you there? What did you think? I'm curious. Was there a noticeable temp increase by latter part of the match?
I think we have been through this before Yes. It was warmer. But just the same as Malaysia - in fact, if you look at the Thomas Cup Final in stadium negara 1992, I think 1992 must be worse.