Comfort! Everyone wants comfort. Air-conditioning systems have been invented for
purpose of providing comfort to inhabitants of buildings. The science of psychometry was developed to understand properties of air - temperatures, humidity and heat values.However, human body, a marvelous piece of creation can adjust itself to changing climatic conditions to provide comfort to owner. It has become quite common knowledge that sweating and their evaporation cools down body.
Have you tried wrapping yourself in a plastic sheet? You will feel warm because of air trapped within sheet. However, after a while, you will sweat and you will feel very uncomfortable indeed. Why?
It has to do with what air-conditioning people call comfort zone. According to them, most people will feel comfortable between 70 to 78 degree Fahrenheit at about 50% relative humidity wearing light clothing and when seated or at rest and without much wind.
There is also a difference in comfort levels when we do different activities. When we feel comfortable wearing woolen jackets to keep warm while we are at rest, don't we feel uncomfortable when we are running or doing strenuous activities? Clearly just wearing a jacket will not automatically make us more comfortable.
On a hot day, you will want to take off everything. Well, society dictates that you cannot do that, or you will be charged with indecent behavior. Anyway, that's easiest way to become comfortable. The body's thermoregulatory action will make your comfortable automatically.
In nature, body has a very good self-temperature regulatory action. When we sweat, latent heat of vaporization takes away heat from body. However, if sweat were to be evaporated, a person with all sweat glands fully opened up can even feel a chill. Putting on clothing will hinder that process of evaporation.
In cold weather, how would you want to wear just a thin piece of clothing, instead of layers after layers of thick clothing? You don't want to look like an astronaut with their bulky suit, do you? You might look a bit too fat and clumsy!
Moreover, some clothing will retain water, so much so that even when outside is cold, you are actually sweating inside. That's condition of condensation. The same thing happens when a glass of cold water is put in a warm atmosphere. The water comes out from air around glass and become water droplets. Your body becomes wet from your perspiration.
