With heat warnings in effect across large parts of the country, many people are noticing unexpected changes to their mental well-being. Intense weather often reduces overall productivity, leaving individuals feeling disconnected and unable to focus properly.
The Science Behind Heat-Related Brain Fog
Natalie Mackenzie, a cognitive psychology expert from The Cognitive Strategist, explains the science behind the brain fog experienced as temperatures climb. "Brain fog is not a medical diagnosis, but some people describe it as muddy thinking, an inability to make decisions, poor attention, or just not really feeling 'on it' – and it can show up differently to different people. Brain fog is often associated with menopause and perimenopause, tiredness or the heat."
During warmer periods, the brain prioritises cooling the body by directing blood toward the skin. This natural process alters how internal systems distribute resources. "Our hypothalamus, which is the brain's thermostat, constantly monitors body temperature and makes sure that when our temperature goes up, that our body cools down through sweating. Our heart rate also increases during the heat, which diverts a lot of energy and blood flow away from the brain, which can affect cognitive function. Things like attention and concentration, which are at the bottom of the cognitive pyramid, tend to be affected first," says Mackenzie.
Impact on Memory and Problem-Solving
These internal shifts trigger a chain reaction that harms short-term recollection. When basic focus becomes difficult, storing new details for later use becomes nearly impossible. "This creates problems with filtering, distraction, and focus, which then impacts working memory, which is in the next layer of the pyramid. This is because if people can't focus and attend, then they can't keep things in their working memory, can't hold information and can't manipulate it to then put it into longer-term memory," says Mackenzie.
Complex problem-solving abilities also suffer. "People can't weigh up information as much, processing speed slows, and people often experience a cascading effect that goes down the different cognitive domains," she explains.
Emotional Effects of Heat
The heat also takes a toll emotionally. "Some people find that because their decision-making is impaired, or because their body feels under stress, this can impact their emotional responses," notes Mackenzie. "In the heat, our blood flow and body is focused on our survival instincts of cooling down, which can make us go into a more emotional state. People often feel more snappy, and potentially more reactive and impulsive, in the heat because they are not utilising those executive functions as well as they usually do."
Warm nights frequently disrupt sleep, harming emotional balance the following morning. Missing deep rest prevents the brain from performing vital maintenance. Mackenzie says: "We want to see a little dip in body temperature to get into that deep sleep state that we need for restorative sleep, but when it's hot, this can be an issue. Less time in this deep-sleep state impacts our sleep architecture, which then impacts memory consolidation and can impact the glymphatic waste clearance process [which keeps your brain tidy by clearing out waste while you sleep, according to the Cleveland Clinic]. Then the following day, you get the compound effects of the cognitive impact of poor sleep."
Practical Tips to Protect Your Mind
Fortunately, there are straightforward steps to take. Mackenzie recommends the following strategies:
- Stay hydrated: Sweat more during a heatwave means replacing not just normal intake but also fluid lost through sweating.
- Adjust your schedule: Start work earlier when it is cooler if possible.
- Change your environment: Avoid hot offices and stick to cooler spaces.
- Align demanding tasks with cooler times: Do cognitively demanding tasks in the morning or early evening; avoid important decisions during peak heat.
- Have a slightly cooler shower: Lower body temperature with a cooler shower, focusing on wrists and neck to reduce the hypothalamic response.
- Create a cool sleeping environment: Use fans, no sheets, and light cotton to improve sleep quality and deep sleep.
