Granted, I started the walk on the thirsty side, but we travel this route a couple times a week without consuming any liquids. Plus, I'd trekked four miles at Medoc Mountain (report forthcoming) the previous week on only one little bottle of Gatorade, so I dismissed my need for water on this occasion.
Mistake. I had to cut the walk down to 2.2 miles and I still barely made it home. My Desktop Weather Channel severe weather alert told me why. During prolonged periods of intense heat, one is more likely to become dehydrated.
I contacted friend, fellow hiker, and nurse, Brenda Wiley, and posed the question about necessary fluid intake. Her knowledge and subsequent research revealed some interested facts. In addition to the standard "equivalent of eight glasses a day (64 oz) in food and water when consuming 2000 calories/day", she discovered urine color is an excellent indication of hydration--a hydrated person usually has clear, pale yellow urine. Thirst is another. The Institute of Medicine of the National Institutes of Science "indicates thirst is an acceptable guide for controlling (fluid intake)".
Oh my. I guess Sprite's copyrighted, trademark logo is right: Obey Your Thirst. (People in humid areas, that goes doubly for you. We learned that lesson in Kauai.)
Always check with your doctor to learn more about these issues, and especially if you're experiencing unusual or constant dehydration. If you've had your physical and everything is hunky-dory, then consume plenty of fluids during the day, and especially before you engage in outdoor activities. And if you're thirsty, even a little bit, for Pete's sake, drink something before you go outside. I almost ended up flat-faced on the side of a country road because I didn't. What would have happened if the same occurred during that four-mile hike at Medoc Mountain? I hope I never find out.