How We Fight Summer Heat

Summer is here and our thermo-regulation system will be pushed to the limits. Did you know that the human body is more resistant to cold than it is to heat? The fact is that we have physiological mechanisms more effective for combating the cold than the heat.

Temperature is a parameter characterizing the heating stage of a physical system while heat represents the energy transferred from one body to another via a thermal process. In other words, we have a constant temperature of about 37oC, which we maintain by losing or gaining heat, depending on the case and necessities.

Normally, we produce a little over 0.5 liters of sweat in 24 hours. In the desert, we can sweat over one liter of water per hour. The apocrine glands develop at puberty and are much more complicated than the eccrine sweat glands. For long, it was thought that only animals produce pheromones. Recent researches proved that the apocrine glands produce human pheromones.

Basically, the sweating is effective as long as the air is not too humid (that is, too charged with water vapors). In a dry environment, the human body can stand temperatures of up to 130oC by sweating, while in a wet environment 49oC are too much to stand even if only for a few minutes. 100% humidity of the air means the maximum water vapor amount that can be contained in the air without the vapors turning into a rainfall.

The evaporation of 2 grams of water is enough to decrease by 1o C the rest of 998 grams of water in a liter. Besides the nervous control of the thermoregulation, there is also the hormonal control, via the hypophysis, thyroid and adrenal glands.