Geez! It’s hot! The dangers of extreme humidity must be carefully considered

A blood red sun sets in the West, followed by a heatwave later on Tuesday evening. Picture: Doctor Ngcobo

A blood red sun sets in the West, followed by a heatwave later on Tuesday evening. Picture: Doctor Ngcobo

Published Jan 18, 2023

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Durban and other parts of the country are currently gasping for cool air as excessive heat waves grip the nation.

I know it gets hot in other places too but the heat in Durban is different, the humidity slaps you in the face as soon as you step out of the safety of an air-conditioned building.

It’s so hot, even our resident hadeda’s haven’t made any announcements for the last few days.

This article should be called “How to cope when the sun hates you” but my editors would certainly frown upon that as we cannot request comment from the sun. Kidding, please don’t fire me.

Humidity is simply a measure of how much water vapour there is in the air. There are two primary definitions of humidity, specific humidity and relative humidity.

Specific humidity is a measure of moisture content – how much water vapour there is relative to the total moist air mass. Relative humidity is a measure of how saturated the air is. This basically means how much water vapour the air contains compared to the maximum it could contain at a given temperature.

Our trusted weather service said on Monday that “a heatwave with persistently high temperatures is expected over north-eastern parts of the Eastern Cape until Wednesday and until Thursday in KZN.”

Great. A quick look at the South African Weather Service (Saws) website shows that Durban is looking at maximum temperatures in excess of 28°C until next Monday, and with daily humidity averaging around 70%, we’re in for a hot and sticky weekend too.

I know that temperatures in other areas of the country can soar to 40°C, but without humidity, it’s still somewhat manageable. For example, Johannesburg topped out at 29°C today with 35% humidity, Pretoria hit 30°C also with 35% humidity and Cape Town, 31°C with 60% humidity.

Durban on Monday peaked at 34°C with 75% humidity and we’re not even in our warmest month of the year yet – February. Heat is manageable but throw in high humidity and it’s a whole other ballgame.

This combination of extreme heat and high humidity can be deadly and may lead to many unexpected health issues, according to medical experts. From heat stroke, brain disorders to depression, high humidity can affect your health in a number of ways.

While intense heat waves can cause dehydration, heat stroke, skin issues, heart-related illnesses, high humidity can accelerate its impact on the body making fainting attacks, heat strokes, heart attack and mood disorders a common occurrence.

This happens because the body finds it difficult to cool off when the moisture stays on the skin for too long. In order to lower our core temperature when it gets too hot, our body will attempt to release this heat by sweating.

According to Healthline, when your body starts to sense that it is overheating, it begins to sweat as a way to control its temperature. “By promoting heat loss through evaporation, sweat helps regulate our body temperature,” explains Dr Adele Haimovic for Healthline.

The combination of high heat and humidity can compromise the human body’s ability to cool itself via sweat. According to Climate Central, the evaporation of sweat from skin cools our bodies, but higher humidity levels limit evaporative cooling.

As a result, we can suffer heat stress and illness, and the consequences can even be fatal. We’ve seen these dangerous effects in rates of heat-related illness across the country this summer.

These some tips for staying safe during a heatwave, according to the US National Integrated Heat Health Information System:

● Never leave children or pets alone in closed vehicles.

● Drink plenty of water; even if you do not feel thirsty. Avoid drinks with caffeine. Persons who have epilepsy or heart, kidney, or liver disease; are on fluid-restricted diets; or have a problem with fluid retention should consult a doctor before increasing liquid intake.

● Check on family, friends, and neighbours who do not have air conditioning and who spend much of their time alone.

● Check on your animals frequently to ensure that they are not suffering from the heat.

● Stay on the lowest floor out of the sunshine if air conditioning is not available.

● Avoid strenuous work during the warmest part of the day. Use a buddy system when working in extreme heat, and take frequent breaks.

● Dress in loose-fitting, lightweight, and light-coloured clothes that cover as much skin as possible. Avoid dark colours because they absorb the sun’s rays.

● Protect face and head by wearing sunblock and a wide-brimmed hat.

● Postpone outdoor games and activities.

● Stay indoors as much as possible and limit exposure to the sun.

Stay safe South Africa!