Many countries across Asia and Europe have been hit with an intense heat wave that sees temperatures reaching all-time highs. News of chocolate bars melting away on grocery shelves to fishes cooked alive in ponds provide snapshots of just how extreme the heat is. Dehydration, overheating, and exhaustions are very real dangers, especially for those who work and exercise outdoors.
Aside from taking a toll on the body, heat also impacts our neurological system. High temperatures can leave us groggy and slow and, in extreme cases, might even lead to permanent brain cell damage.
According to clinical neuroscientist Dr Elisabeth Philipps, sweltering summer days can leave us in a state of heatwave brain fog and cause brain function to go down.
"Higher temperatures can stop nerve fibres from working properly. This sometimes means messages cannot get to and from the brain, which is why you may experience fatigue, weakness, or problems with balance or vision," says Philipps, who works with health and wellness brand fourfive.
When the brain reaches 40 degrees Celsius, the blood-brain barrier begins to break down; the brain becomes vulnerable to bacterial infections, and oxygen flow slows.
"Unwanted proteins and ions can build up in the brain, often causing an inflammatory response and negatively affecting normal functioning. The effects can be detrimental to those with preexisting conditions such as Alzheimer's or multiple sclerosis.
Aside from these permanent damages, cognitive functions can also be temporarily dampened. A 2018 study observing high school students in New York found that students performed on average 14 per cent worse on days when temperatures reached higher than 32 degrees Celsius. Students are also 10 per cent less likely to get a passing score on exams.
A study found temperature impacts productivity in the office environment as well. Productivity decreases when the mercury hits above 23 degrees Celsius and is slashed by close to nine per cent when it exceeds 30 degrees Celsius.
Extreme heat clouds judgement and athletes like tennis players can affect their strategies and reactions to their opponents on the court. High temperatures are correlated to cases of anxiety and stress and increase the likelihood of hospitalisation.
One of the most important things to keep in mind, says Philipps, is to rehydrate to compensate for excessive sweating, the body's regulatory mechanism to cool down the body.
"Even 1 to 3 per cent dehydration can lead to reduced brain neuronal activity, impaired cognitive function, low mood and fatigue," she says.
She advises at least drinking two litres of water a day and adjusting depending on body mass and physical exertion. Avoid diuretics such as caffeine and alcohol as they cause further dehydration.
Other signs of heat exhaustion include dizziness, confusion, loss of appetite, and feeling lethargic. At the onset of these symptoms, get out of the sun and into loose-fitting clothes or try hitting the showers to lower body temperature.
Also see: Extreme heat can help and hurt performance – here’s how to manage and use it to your advantage
