Summer may be almost over but many parts of the country are still experiencing hot weather. Like politics and many of the issues that fill the news every day, many people find that summer heat is very wearisome and fatiguing, but unlike politics and the news, they aren’t quite sure why the summer heat is so tiring.

With the news of politics, one can always tune them out or turn them off and escape. With the heat, unless you are in an air-conditioned car, home or building, you can’t escape the heat and its effects. Just stepping outside and going to or from the car, home or building and you’re in the dreaded heat.

But why does the heat make you feel so tired and fatigued and why does it feel harder to breath?

It’s the cost we pay for being warm-blooded – meaning we maintain a constant body temperature.

In the winter when we get cold we shiver. That’s the body’s way of producing heat to keep the body’s temperature war enough. But in the summer heat, the body needs to find ways to get rid of excess heat and doing that has a cost. Believe it or not, your body has to work more than normal to shed excess heat and that takes energy and using energy can lead to being tired and fatigued.

Allow me to explain.

One of the things your body does in the heat is known as vasodilation which means your blood vessels dilate to allow more blood to flow closer to the skin. As the blood travels below the skin, excess body heat is dissipated through the skin. If you touch the skin of someone that’s been out in the summer heat, their skin will feel hot to the touch. Some of that may be a result of sunlight, but a large part of that hot feeling is the body shedding excess heat.

Your body also sweats when it gets hot. Sweating actually serves a dual purpose. The sweat on the surface of the skin evaporates which helps to cool the skin. Secondly, as muscles work they produce lactic acid. If allowed to build up in the muscles, lactic acid will suffocate the muscle cells, which makes them fatigue and possibly cramp. One of the ways the body uses to get rid of the lactic acid is through sweat and it’s the lactic acid that gives sweat that smelly body odor.

Vasodilation of the blood vessels and sweating makes your heart and metabolic rate increase. Your body burns more calories when it works and the burning of calories generate heat, which also has to be eliminated. The heart has to pump faster and harder to keep the blood flowing through blood vessels that have expanded – dilated.

All of these things require the body to work and burn more energy and the more energy the body burns, the more tired and fatigued a person feels.

Most people also fail to drink enough water when they are in the summer heat. They drink other things like soda (pop), beer, iced tea, fruit juice, etc., but none of these help hydrate the body like water and can add to a person becoming dehydrated in the heat and that dehydration makes you tired.

But why is it so hard to breathe on days like the one when I’m writing this?

At the time of writing this post, it is currently 96 degrees in the direct sun, a dew point of 71 degrees, making the heat index climb up to 105 degrees.

A high humidity or dew point means that there is more water vapor (molecules) in the air. A given volume of air can only hold so many molecules of nitrogen, oxygen, water and other gases. The hotter the air, the thinner the air and the less molecules it holds. This is why hot air balloons and helicopters have more problems flying in high summer heat than in the winter.

As humidity and dew points increase, that means there are more water molecules in the air and less oxygen molecules. As oxygen molecules are replaced by water molecules, it becomes harder for a person to catch their breath, especially people with respiratory conditions. That’s why it’s harder to breathe in hot tropical climates than it is to breathe in the hot desert.

I’m originally from Arizona where there have been times when the temperature has been over 110 degrees, but the humidity is below 10% and breathing isn’t a problem. But in places like the southeastern US and other locations where the humidity and dew points are higher than the Arizona desert, breathing is more labored and tiring for that very reason.

So, this time of year, chalk up being tired of the politics and news as a mental fatigue, but being fatigued outside is because you are warm-blooded and your body is working hard to stay cooler.