Hydration in a heat wave

I went for a 17 mile training walk on Saturday. I started at 9:30 am and it was already 85 degrees. It was forecast to be 95 degrees with a 105 degree heat index. I was walking on a trail that is a 3.3 mile loop so that I was back at my car for snacks and more to drink every 3.3 miles (like a pit stop on the event). I had had 20 ounces of water before my walk and started my first lap with 20 ounces of Gatorade and 40 ounces of water. I knew I needed to be drinking a lot because it was going to be soooo hot. I drank those same amounts of water and Gatorade each lap. I stopped for lunch after 3 laps (10 miles). When I got up from lunch and was ready to head out again I got about 5 miles down the path and started feeling light-headed and dizzy. I decided to call it a day as it was just too hot and apparently I was dehydrated despite all the drinking I was doing. I now know why they say you need to be drinking extra water/sports drink the whole day before a long workout in the heat. I then read that in extreme heat your body can not replace fluids as quickly as you are losing them. Some experts suggest drinking an extra 64 ounces of water the day before a long walk in the heat. Everyone sweats different amounts so the exact amount of water you need the day of or the day before will vary. The important thing is to drink extra and avoid those things that will dehydrate you like sodas and alcohol.

A good way to tell if your staying hydrated is to weigh yourself before and after your training. You should weigh the same or slightly more (considering your eating during training too). If you weigh less you didn't drink enough. If you weigh more than a couple pounds more than you did before your drinking too much. It is better to drink more than less, just be sure that it is a combo of water and sports drinks.

Also, remember the clear urine test. If you have dark colored urine you are not drinking enough. Your urine should be light yellow or even clear.

Good luck staying well hydrated as the heat of summer sets in on us.