Physiologicaly...
The hot, the cold, and the alcohol work against you. What goes in your stomach goes next to the blood, the heart, and then circulates. The brain, getting much of the circulation, gets warmed or cooled before the rest of the body. The thermostat is in the brain so it then tells the rest of the body you are warm or cool before the body is warm or cool. Thus the body starts loosing heat (if it thinks it is warm) or gaining heat (if it thinks it is cool) before it really is warm or cool. i.e. you over heat or over cool by consuming cool or warm liquids. But does it make a difference? Probably only when guzzling lots of ice water. Sips of hot stuff are not likely to have a significant temperature difference by the time they reach the brain. Alcohol, OTOH, does make a significant difference and can increase your risk of hypothermia and dehydration. It dilates the blood vessels of the skin and thus makes your body a radiator. This feels good (because it warms the skin) but take heat away from the vital organs. (like your brain) In hot weather it dilates the peripheral vessels and increases sweating. It also is a diuretic. Both of these things increases dehydration. But gees, if a sailor were to follow all that technical stuff, how can we have fun? Well, have fun, but when temps or exposure times are extreme remember the above. It can make a difference.Geoff