Behind the Forecast: Worse than heat? How humidity can be dangerous

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Science Behind the Forecast: Worse than heat? How humidity can be dangerous

LOUISVILLE, Ky. (WAVE) - While temperatures increase as we head into the summer months, the heat is the main focus, but we can't forget about the humidity.

Humidity, more specifically relative humidity, is the "measure of the actual amount of water vapor in the air compared to the total amount of vapor that can exist in the air at its current temperature," according to the National Weather Service. Warmer air can hold more water vapor than cold air.

Our bodies release heat in a few ways once our blood is heated to more than 98.6°: by varying blood circulation rates and depths, sweating, and even panting.

Releasing sweat does not cool us off until the water evaporates. This works because the heat energy needed to evaporate our sweat is pulled from the body, cooling it down. High humidity can keep that evaporation from happening.

When humidity is high, moisture remains on our skin longer, which makes us feel hotter. To compensate, we sweat more. Excessive sweating can lead to the body losing water and chemicals that are vital to its proper function. Our core body temperatures rise as we're unable to cool down, eventually leading to overheating.

High humidity can negatively affect your body, causing us to feel lethargic. It can even lead to hyperthermia since the body is unable to effectively release heat. Hyperthermia can lead to:

  • Dehydration
  • Fatigue
  • Muscle cramps
  • Heat exhaustion
  • Fainting
  • Heatstroke

Humidity can affect not only your body but your mind. Some psychologists posit that humidity can influence chemicals in the brain that affect moods.

In 2018, heat stroke killed more people in the U.S. than hurricanes, tornadoes, and lightning combined. Know the signs and symptoms of heat-related illnesses and treat them as medical emergencies.
In 2018, heat stroke killed more people in the U.S. than hurricanes, tornadoes, and lightning combined. Know the signs and symptoms of heat-related illnesses and treat them as medical emergencies. (Source: National Weather Service)

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