I wear a Buff, immersed in water and wrung out, on my head, UNDER a 2-3 inch brimmed "bucket" hat. Living here in South Florida, I have a collection of such hats and usually take the most ventilated on Camino, depending on the weather forecasts.
Presently the choice is between a tan North Face ultra-light weight hat, and a tan Outdoors Research (OR) bucket hat. Both are very good, but the North Face hat is softer, lighter, and handles being soaked in water better. BOTH have a neck / chin strap / string. This is important on a windy day...
If you soak a Buff in water, wring it out and put it on so it hangs over your neck (like a pirate - sort of), you accelerate evaporation which provides a transpiration-based cooling effect on your head and neck. Soaking and wringing out the hat does the same thing. It makes a big difference when walking the Meseta...or anywhere on Camino where there is no shade.
Also, you can wet a Buff and wear it around the pressure points on your wrists or around your neck, again to use evaporation to cool your core temperature. I carry two Buffs, one in each rear pocket of my hiking pants.
Lastly, DRINK WATER. ADD electrolyte powder or tablets. I use Nuun brand tablets in a bottle of water. There are many other brands available. I get mine in a runner's store, but they are available online.
Also, add bananas and oranges to your diet. They make excellent mid-morning snacks. Both contain significant amounts of potassium, calcium and magnesium, not to mention fructose. These commonly available fruits will help maintain your electrolyte levels while you are sweating like the proverbial pig.
Carry the fruit peelings with you to the next proper trash can. Please, DO NOT dispose of them on the trail. They DO NOT decompose fast.
While walking, should you STOP SWEATING, FEEL LIGHTHEADED OR DIZZY, or be unable to urinate, or your urine turns darker than normal, STOP WALKING and get to shade. You are likely experiencing heat stroke or sunstroke. This can happen even on an overcast day with a gentle breeze. See the urine evaluation chart below.
In 2015 while walking from Porto to Santiago I took three "dirt naps" while walking along by myself. They were later determined to be dehydration induced syncope (fainting). I have since resorted to forced hydration. I consume .5 liter each hour whether I feel I need it or not. Every other hour is an electrolyte enhanced drink, using the tablets previously mentioned.
Also, use some of the above evaporative techniques to lower your core temperature. Ingest electrolyte replacements and water.
I am including a .pdf of a urine chart that explains how to evaluate the color of your water output...
I really hope this helps someone...
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