Heatwave, your health: From dehydration to heat stroke

Walter Chingwaru Correspondent
It is official — Southern Africa is going through a massive heatwave, with temperatures soaring to above 40 degrees Celcius mostly in low-lying areas of Zimbabwe — the Zambezi and Limpopo valleys — parts of South Africa, Mozambique, Zambia, Lesotho, Namibia and other areas.

Zimbabwe’s Meteorological Services Department has issued a warning that the country will continue to experience extreme temperatures above the average for the month of October, forecasting that the country might have experienced record-breaking highs during the week ending October 27 (last week).

These areas include Kanyemba, Kariba, Binga, Victoria Falls, Beitbridge, Chiredzi, Chisumbanje and Chipinge.

In fact, a number of areas reportedly experienced sweltering heat during this period. With the ongoing changes to the global climate, heat waves may become a frequent phenomenon in the region.

The MSD has warned that: “Given the extended period of very hot conditions the public is encouraged to; stay well hydrated, put on sun hats when working in the open, avoid extended exposure to direct sunlight and take measures to reduce heat related problems”.

The immediate effect of high temperatures on your body is dehydration.

So what are the symptoms of dehydration?
The common symptoms of mild to moderate dehydration are dry mouth or tongue, thirst, headache, lethargy (lack of energy and enthusiasm), fatigue, dry skin, muscle weakness, light-headedness, dizziness and a lack of focus.

Cases of severe dehydration can present sunken eyes, lack of tears, sunken fontanels (specifically among infants), hypotension (low blood pressure), tachycardia (abnormally rapid heart rate) and, in the extreme cases, it can lead to unconsciousness

Dehydration is also known to lead to hypoglycaemia (a spike in blood sugar levels). Reports state that people suffering from diabetes must stay well hydrated to avoid hyperglycaemia!

Further, dehydration can increase your risk of getting urinary tract infections (UTIs). UTIs are more frequent in older adults, especially women. The flow and frequency of voiding urine affects the rate removal of bacteria from your urinary tract, so hydration enhances your body’s ability to fight UTIs.

So what are the main health risks of a heatwave?
Dehydration: when the body doesn’t have enough water. This is one of the best known effects. What are the effects of insufficient water in our bodies? We all know of the adage ‘water is the source of life’, meaning without it there shall be no life.

Your bodily functions, specifically, the physiology of your cells, tissues and organs depends of the availability of water. Water is the medium in which all bodily processes take place.

Besides, water is the main component of blood plasma (92 percent), the fluid that makes up your cell volume (intracellular fluid or cytosol) (70 percent) and the extracellular fluid — the fluid that bathes your cells.

In fact, water constitutes approximately 60 to 70 percent of your body mass! Therefore, biologically, your body is a mass of bones, tissues, salts and water. Maintaining the right balance in your composition of water and salts is important for optimal bodily functions.

Heat exhaustion: When you become very hot and your body loses water or salt. Symptoms include headaches, weakness, muscle cramps and feeling faint or sick.

Heat stroke: Despite being less common than heat exhaustion, it is more dangerous. In fact, heat exhaustion is a major risk factor for heat stroke. Heatstroke occurs when your core body temperature rises above 40 degrees Celsius.

Symptoms of heatstroke include profound changes in brain function, meaning alterations in consciousness or mental status. Heat stroke increases your risk for permanent brain, heart and kidney damage as well as the risk of death.

Sunburn: High temperatures as well as sunny conditions put people more at risk of getting sunburnt — a condition with short to long term effects. Generally, heat waves — which are often characterised by profuse heat and extreme sunshine —come with above average ultraviolet radiation. UV is blamed for a number of skin cancers.

However, it must be known that skin cancers are a delayed effect, with the condition possibly taking 20 years after exposure to appear.

Typically, sunburn appears roughly six to 24 hours after exposure to very sunny conditions.

What do you have to do in a heatwave?

Below is a list of things to do to mitigate the effects of a heatwave.

Drink plenty of water.
Stay out of direct sunlight.
Stay in an air-conditioned room, if possible.
If you have to be outdoors, wear loose-fitting clothes and a hat.
Never leave people or animals in a hot car.
Keep an eye on your neighbours, friends, family and pets.
If you are going to be in the sun, to avoid sunburn, apply a sunscreen, if available.
Heatstroke is a medical emergency that requires urgent medical attention. If you feel that you have been exposed to- or are suffering from extreme effects of heat wave, please seek medical attention.

Professor Walter Chingwaru is a Biomedical Scientist and current Chairperson of Biological Sciences at Bindura University of Science Education. His research interests span the area of Biomedicine, with an ardent interest in public health issues. Feedback: Twitter – @walterchingwaru, Email: wchingwaru@buse.ac.zw, Phone: +263777766606.

Source :

The Herald

Check Also

Zimbabwe: No Need to Look for Scapegoats – Sithole

Veteran sports administrator, Tommy Sithole, believes there is no need to look for scapegoats after …

This function has been disabled for Zimbabwe Today.