Humidity is the measure or amount of water vapor in the air. It could be relatively low or high depending on weather conditions and change slightly in a given day. This measure is also commonly referred to as relative humidity and shown as a percentage on weather forecasts. A high humidity indicates precipitation, fog, or dew is likely to occur but it also indicates that it will be more difficult for people to cool down.
Sweating is the human body’s method of cooling down when its internal temperature gets too high. Sweat is produced by sweat glands in the skin and the sweat evaporates off of the skin which produces a cooling effect due to the change in state from liquid to gas and cools the body. Without this ability, the body could become so hot that heat stroke would occur and this condition can lead to organ failure and death if not properly treated or the temperature is not reduced.
The humidity of the surrounding air will therefore affect the body’s ability to cool off. The more water vapor that is present in the air, the less sweat will evaporate off of the body and cooling is reduced with increasing humidity. If the humidity is 100% and the air is completely saturated with water vapor, then no sweat will evaporate off of a person’s body. This means that in high humidity environments, it is much more difficult for a body to cool down or even impossible for the body to cool down through sweating.
Feeling hotter than what the temperature says
High humidity also accounts for the feeling that the temperature is much hotter than what a thermometer indicates. The human body is very sensitive to temperature and when the ability to cool down from sweating is reduced by humidity, the temperature will feel warmer than it really is. For example, in 75 degree Fahrenheit weather with 100% humidity it will feel like 80 degree weather.
People have always blamed health problems or aches and pains on the weather but in some cases it is true. High humidity areas have been linked to causing other health effects. Preexisting medical conditions such as asthma, rheumatoid arthritis, and osteoarthritis can flare up with high humidity. Asthma may even flare up in high humidity without the presence of allergens in the air. Fatigue is also prevalent with being in a high humidity environment for a prolonged period of time. Because the body is not able to cool off properly it expends extra energy leaving a person feeling fatigued or sluggish.