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In our world, deeply connected, over the course of the day, it’s not unusual to feel “drained”, unable to focus or make even a simple decision. This phenomenon has a name: cognitive fatigue. But what is it exactly? And why does our brain sometimes feel like an overloaded computer?!
Cognitive fatigue refers to a suboptimal physiological state induced by a sustained mental effort. It is characterized by a loss of concentration, short-term memory lapses, a rise in irritability and a difficulty in decision making or problem solving. Like any other organ, the brain requires energy to work and cannot be fully active for an unlimited amount of time. When we push it too hard, it consumes a large amount of energy leading to a gradual depletion of cognitive resources. In response, the brain shifts into a kind of energy-saving mode, trying to maintain performance while signaling the need for rest. If these early signs are ignored, performance can suddenly decline, increasing the risk of errors and mental overload.
We are not all equal when it comes to this phenomenon, the anatomy and functioning of our brains, which are unique to each individual, play an important role. This refers to the concept of cerebral and cognitive reserve. If we imagine our brain as a computer, the cerebral reserve is like hardware, it is the physical characteristics of your brain (number of neurons, synaptic connections, brain volume…) while the cognitive reserve is your software optimization (how your brain uses its resources, shaped by education, life experience and cognitive stimulation). Like a computer, with more RAM and a faster processor, can handle heavier tasks without crashing, your brain with a greater reserve can better resist cognitive fatigue, adapt to challenges and recover from overload. However, even the best systems have limits and need regular updates (cognitive training) and downtime (rest, sleep or mental breaks) to maintain performance and prevent burnout.
Cognitive fatigue is not a new problem, but it is amplified by modern lifestyle. Main causes are:
1) Hyperconnectivity due to the increasing number of screens and notifications that constantly fragment our attention.
2) Multitasking, it is when you constantly switch from one task to another, particularly at work (for example participating in meetings, taking notes, and responding to emails at the same time).
3) Reduction in rest time for our brains, moments of true disconnection.
Taking all this together leads to an increase in cognitive fatigue which, if not taken seriously and accumulated day after day, this state can evolve into chronic mental exhaustion, ultimately increasing the risk of burnout.
So, take care of yourself and have a break!