top of page

Cognitive Function

A labelled diagram showing a silhouette of a thin dark skin person using purple forearm crutches. The labels read, “lowers cognitive functioning - mood, links to dementia”, “lowers immune response, more prone to colds”, “affects blood glucose control, risk of type 2 diabetes”, “risk of cardiovascular disease”, “vaccinations less effective”. Underneath the person, text reads “ways lack of sleep affects the body"

Cognitive function explained

Cognitive function refers to the mental processing your brain does when you concentrate, remember, learn, and reason. A person with cognitive dysfunction might have trouble focusing their attention, remembering facts, or understanding information someone is trying to tell them. As a result, cognitive dysfunction can affect a person’s ability to make informed decisions and to act quickly on those decisions. What many people call “brain fog”—when your mind feels sluggish and you can’t think clearly—is an example of cognitive dysfunction.

Cognitive functions like learning and reasoning rely on our working memory to process information. Working memory is where we take in new information and integrate it with what we already know. But we all have a limited working memory: it can only store a few items at a time, and if it’s overwhelmed, it can’t process the information we try to take in. You can think of your working memory as a container: if it overflows with information, it can’t process properly. So your working memory could be overwhelmed if the size of that container is small or if there is too much for the container to hold at one time.

Disability and cognitive function

People with ADHD, dementia, or traumatic brain injury may have a lower working memory capacity than non-disabled people (in other words, a smaller container). Disabled people also often have more thoughts and worries taking up space in the container, leaving less room to hold information they might need to learn. For example, a person with incontinence might have to make a mental map of all of the public washrooms they might have to use if they go out. A person with episodic disabilities like someone with MS might have to worry about ableist comments or microaggressions from people who see them parking in a disabled parking spot. Intrusive thoughts, traumatic memories, and worries about access to food, housing, and health care can all take up space in working memory and affect mental processing.

Heat and cognitive function

Heat can have a negative effect on cognitive function in many overlapping ways:


Staying hydrated and finding ways to keep your body cool, like air conditioning, ice packs, and cool showers or baths, can help reduce the negative cognitive effects of heat. Your brain also needs energy in the form of glucose to work, so although some people lose their appetite in hot weather, reminding yourself to eating or drinking foods that give you sustained energy can help.

bottom of page