I have read a couple of things that say Drinking cold water constricts your organs slowing digestion. I have always herd that cold water is better for you especially during the summer months. I know there was a bogus article floating around about dogs getting sick from drinking cold water and this seems to be along the same lines. Any inputs on this?
This has been researched and as is often the case there is conflicting information. Part of the problem is that the studies generally use one temperature for the “cold” water and one for the “warm” water. The few research studies that actually used a range of temps that I read some time ago are like many other studies, it seemed like the findings were what you would most likely do anyway.
Very cold and warm water were not recommended. Cool water was the overall winner in the studies. Participants were much more likely to drink cool and cold water, but tend to drink more cool water. The colder the water, the slower the rise in body temperature, but again at a point the colder water was consumed more slowly/in less quantity. Cool and cold water showed faster absorbtion rates, that is, they increased hydration more quickly.
The current recommendations from the ACSM is to drink about 20 oz. of cool water (or sports drink, which I do not recommend as a pre-hydration beverage) in the 4 hours prior to exercise, about 12 oz. 15 minutes prior to exercise, and that haveing a small amount to eat with the beverage aids in stimulating thirst and water retention.
During exercise ACSM recommends about 5 oz. of water every 20 minutes for exercise lasting an hour or less. And switching to a sports drink for exercise lasting more than an hour. I am pretty sure the recommendation was not more than a quart per hour, which I tried to do once as an experiment and it took some serious will power to drink that much water/sports drink.
After exercise they recommend that you drink 20 oz. of water per pound of weight lost during the session, as the weight lost during the session would be almost entirely water. I remember wondering why there was no timeline for consuming the post workout water. I would assume it would go with the 5 oz. every 20 minutes recommendation as drinking that much water in one go feels counter intuitive.
They also had an interesting color comparison scale that correlated urine color to hydration. Again, as you would expect, darker urine means more dehydrated.