The first requirement for survival is maintain our core body heat. This means keeping it within a few degrees of 98.6. If we go too much higher or lower than this, it can have serious consequences, even leading to death. But we usually concentrate on the low side, forgetting that high core body temperatures are just as dangerous, causing similar symptoms.
Any time the ambient temperature is higher than our body’s core temperature, it prevents our bodies from radiating heat. Worse than that, if we are doing any serious physical labor, our muscles are producing more heat that needs to be shed somehow. But when we sweat, the normal way for our bodies to shed heat, the sweat doesn’t just absorb heat from our bodies, but from the ambient air as well, reducing the effectiveness of that cooling method.
So, how do we keep from overheating in those circumstances?
Do Heavy Work at Night
It can help greatly to change your schedule, in order to take advantage of the cooler part of the day. That’s where the idea of the siesta came from. Either do the bulk of your work at night, when it’s coolest or as close to night as possible; such as early in the morning. I life in a hot part of the country and I have long since made it my habit to mow the lawn early Saturday morning, before it gets too hot to work outside. Then, when it’s warmer, I work in my workshop, which is at least in the shade, with a fan running all the time.
With perspiration being an important part of our body’s ability to shed excess heat, it’s important to make sure we are able to continue perspiring, even when involved in heavy work. I’ve known people whose bodies don’t perspire normally and they all have problems with the heat. One woman in particular would just about pass out if the temperature rose above 80 degrees.
Surprisingly, the body can sweat out as much as 3 to 4 liters of water per hour, when doing heavy exercise or physical labor. That greatly increases our water consumption requirements in times when it is hot and we are working.
Stay in the Shade
One thing that anyone who lives in hot climates will tell you is to avoid the sun, staying in the shade as much as possible. It can be five to ten degrees cooler in the shade, than it is in the sun, both making it easier for our bodies to shed excess heat and lowering the amount we have to perspire, in order to make that happen.
Moving Air Speeds Evaporation
The wind is our friend, when it comes to staying cool in hot weather. As the wind moves across our bodies, the warmer “bubble” of air in close contact with our skin is constantly changing, pulling off excess heat with it. That moving air also speeds evaporation, as the same bubble of air has a higher relative humidity, due to the sweat evaporating off our bodies.
If you can, find a place to do physical work, where you are both in the shade and where the wind will be blowing on you. One such place might be between your home and a detached garage. Both buildings block airflow, so the air tries to get around. That makes the apparent wind speed in the passage between the two higher, helping to keep you cool.