Beat the heat - tips for being in hot weather

I live in the sub-tropical temperate zone, so it never gets too hot or cold here. But, I have travelled and spent some time in the tropical heat, and so, when community member on another site asked for tips to handle hot temperatures, I contributed tips from my experiences. So, please add your tips in the comments.

Image source: Pixabay / selcukyildiz. Free for commercial use.

Acclimatising

The primary way the human body cools is via sweat, pushing water out through pores onto the skin, where the evaporating sweat causes cooling to occur. This method of cooling is effective provided that the outside humidity is not high. When I arrive in hot countries, my body tends to drip with sweat. That's my body continuously pushing out sweat in an attempt to cool down. If you notice, people who live in hot countries don't drip with sweat; they glisten. This is because their bodies have acclimatised over several years to conserve water.
So what does this mean for the sub-tropical visitor? Firstly, I'm going to drip with sweat - a lot. I have to drink much more water than locals and replace electrolytes lost through the sweat. I'm not going to be able to acclimatise, and my visitor schedule probably means I can't employ some of the tricks locals use.
While I can't hope to acclimatise, I can teach my body what to expect. On the day arriving in a hot country, I walk about two hours in the heat. I'm allowed to drink as much water as I need, but I have to walk. That walk is sometimes pure hell, but every activity in the heat after that is easy in comparison.

Hydration

Drink a lot of water. A high-performance athlete told me that the body can only absorb a few mouthfuls of water every fifteen minutes, so if your water usage gets higher, you have to do other things to reduce heat. However, the body can draw water from the bowels for reuse if necessary, so don't get too concerned about getting too far ahead on water. Yes, it is possible to drink too much water (e.g. hyponatremia), but usually, you'll have the opposite problem.
Drink the cleanest water you can. Soda's don't count because sodas take a lot of water to digest all the sugars. Alcohol is also very dehydrating, so reserve it for the cooler times of the days and stick to low-alcohol beers.
A lot of sweating will deplete minerals from the body. Don't get too concerned about this - but I like to drink one electrolyte-rich drink per day. My favourites are coconut water and Pocari Sweat. Eating a banana can also help. I tend to avoid Gatorade or Powerade because of the amount of sugar.

Food

You might have noticed that your appetite changes in hot climates, and you begin to crave certain foods. It turns out your body is smart! The main concept here is that digesting food creates heat and certain food creates heat (thermogenic foods). Typically fats and red meats are the most sweaty, while some people will get sweats from alcohol and cheeses. The least thermogenic food is probably straight glucose because it requires zero effort to digest.
So, how do you use this information? First, reserve the heavy and rich foods to the end of the day when it's cooler and you're back in the hotel with your air conditioner. Start the day with fruit and or easy carbs and avoid too much fat or protein at breakfast. At any meal, consider switching from red meat to chicken or fish because the protein is easier to digest. Have the heavier meal later in the day when it's cooler.
Top up your energy levels by eating fruit throughout the day. While not the zero effort of glucose, the sugars in fruit are easy to digest, and fruit has other nutritional benefits.
Finally, if you're carrying a few extra pounds, then you might suffer from the heat more. It takes more calories to move more weight, and body fat is a great insulator. So, consider losing a bit of weight. Also, if you're heavy like me, you might want to consider improving fitness to get the most out of your time away.

Behaviour

If you watch locals, you'll see they have different ways to beat the heat. Often they'll sleep during the middle of the day. They'll walk slowly and take the long way through shade and breezes rather than running across a sun-baked shortcut. The faster you move, the more heat your body makes, so move slower when hot.
Also, if there is a breezy spot, pause for a little while to allow the breeze to accelerate evaporative cooling on the body. Pretty much anything you'd do to avoid hypothermia in a cold situation, do the opposite in the heat. But, I'd recommend avoiding the aircon-to-aircon dash because it retards adaption to the heat.
Reserve more activity for the cooler times of the day, such as the evening. It's no surprise that people in hot countries tend to rise late and go to bed late too.

Clothing

I prefer to wear one wicking layer close to my skin with a loose button-up shirt over the top. This combination worked because the wicking layer encourages evaporative cooling and reduces the chance of a heat rash. At the same time, the loose shirt creates a breezy microclimate close to the body as I move. That works for me. At SteemFest4, my standard clothing was a merino wool t-shirt with a cotton shirt over the top.
In scorching places, I prefer to wear long sleeves and trousers to reduce direct solar thermal gain on my skin, though if I'm going to be out of the sun, then shorts can work better.
And, what if you ever have to wear a jacket and tie to a ceremony that's outside in the direct sunlight? Firstly, put on my base layer and shirt, then walk about a bit to build up some sweat. Then I cool that sweat with some aircon - like in the car on the way to the event. Finally, I put on the jacket to hold in the cold. Some people put ice-packs in belts that go across their kidneys though I haven't tried that yet.
Earlier I mentioned shade. Well, an umbrella is a great form of portable shade. A good sun umbrella reflects solar radiation and lets no light through. Find a way to carry the umbrella that doesn't require energy. For example, some people tie it to their packs to make it hands-free.

Not comprehensive

I'm sure you have your own tips to beat the heat. Please leave them in the comments below.