It's starting to get hot again. Below are a few things I've learned from a life time of fishing, and working outside. You can make your fishing trip just a little better.
1. Drink two full glasses of water before you go out in the heat. This gives your body a head start on maintaining hydration. Don't drink any more caffeine than you just have to to avoid the withdrawal headache. Caffeine as you well know is a diuretic and will cause dehydration to advance more rapidly.
2. Take plenty of water with you and drink early and drink often. Don't wait until your parched because then your body has to play "catch up" to get enough fluid into the stomach and absorbed and into the circulatory system. Its better to stay ahead of the dehydration curve. Think of it as maintenance, just keep putting water into the system without waiting for the radiator cap to burst off.
3. Wear a wide brimmed hat that allows air to circulate over the top of your head. A straw cowboy hat with holes in the sides of the crown works well. So does a pith helmet like the mail carriers wear. In fact these are the best because they have a suspended head band that allows air to circulate up inside the hat and out again. I have one that is lightly woven, allowing air flow through the hat itself, plus the up and under flow. Do not wear a ball cap. They trap heat against the top of your head, and that's where your body throws off the most heat. They do not shade anything except the face, leaving the neck and sides of the head exposed to the sun. They pull back any hair that might have covered the top of your ears, making the top of your ears extremely exposed - guess where much of skin cancer starts? The tops of the ears. These really need to be shaded.
4. Use the frog tog type bandannas. These cooling devices lay around your neck and work quite well to cool you off plus shade your neck.
5. Learn to recognize the signs of heat exhaustion and heat stroke. One of the signs, and its a hard one to recognize in yourself, is diminished mental capacity. Once your body gets far enough into dehydration your brain is affected. Your thoughts become slower, less organized, and less clear. When you've reached this point you are in trouble, serious trouble. It can really sneak up on you too. When I was working manual labor in construction in Texas summers this happened to me three different times. I finally learned to recognize a state of mind that was kind of based on a stubborn idea that I could beat the heat and just keep going. Doesn't work. You probably want to do a buddy system on this one - keep an eye on each other and watch for signs of dehydration. One of the clearest signs is that sweating stops - a bad sign that one - it means you're in very deep trouble because you don't have enough body water to even sweat anymore. Google "Signs of heat exhaustion/stroke" to get a full description - these are good things to know.
6. Pour cold water on the inside of the forearm from elbow to wrist. It's amazing how fast this can cool you down. Cold water almost hurts when you pour it there.
7. Do not pour ice cold water on your head when suffering from heat exhaustion. This can cause passing out - pour the water as explained above.
8. Take a shade break. Get in the shade. Sit down. Drink water. Do this on a regular basis.
6. As much as it pains me to say this...avoid or minimize alcohol intake. Alcohol actually causes your body to lose water faster, bringing on heat problems faster. I know, I know. A cold beer tastes outstanding when you're hot. Avoid it. Minimize it. Wait until your exertion is over, like when you get back home. Sure I break this advice, well actually I don't - I drink some beer when I'm out in the heat - but not much. One per every two hours at most, and mostly less than that. But then I am pretty experienced at this heat game and part of my strategy is to keep it close to home so that I can get under the AC when I want/need to. If I was on a day long trip in the heat there would be no drinking on my part. Learned this one the hard way too, out deep sea fishing.
7. Avoid eating heavy foods. Digestion takes a lot of water and your body will draw that water out of the circulatory system. Digestion during hot weather will really slow you down. Stick to a few light snacks, small snacks, spread out snacks, and you'll deal with the heat a lot better.
8. If you like the sports drinks have at them periodically. Some of them help keep electrolytes up and balanced. Don't just drink those all day though, you're probably not going to lose that many electrolytes and may over-compensate. Drink water often, and intersperse a sports drink now and then.
9. When I was a kid growing up around ranchers and farmers I saw something that they all did that seems counter-intuitive and is rarely practiced anymore. These were professionals at working in the heat and they wore long sleeved shirts buttoned at the wrist with a t-shirt underneath, and long pants. When they stripped down they were fish-belly white everywhere except from their collars to their hat bands, and their hands. Guess where the term redneck came from. They wore light cotton shirts and pants, not heavy stuff. But they covered all the skin they could from sun exposure. They survived summer after summer after summer this way. They knew what they were doing.
10. Carry a bandana. They're useful in many ways and one of the best is to cover the back of your neck if you're not going to use the frog tog things. Another is to mop sweat off your face. Plus you'll just look cool...
11. Good sunglasses can save your eyes a lot of fatigue from squinting, making you more comfortable during the day.