Symptoms of mental fatigue include a sense of lethargy and an inability to concentrate. It can have serious effects on your cognitive functioning; decreasing your vigilance, secondary task performance and problem solving, and lessening situation awareness.
Below are typical symptoms of mental fatigue:
Inability to concentrate
You can’t stay focused on a task and your mind is wandering. You have symptoms of tiredness; yawning, rubbing of eyes and struggling to keep them open,
Mental fatigue can cause your short-term memory to become unreliable, so if you find yourself forgetting things, for example, appointments.
Trouble with learning
You find yourself unable to remember the steps to a new procedure or comprehend a new idea. Mental fatigue can really impair your ability to learn and remember new things.
Reasoning and judgment problems
Your reasoning is impaired or you fin yourself taking risks.
There should not be any external effects of mental fatigue, as it does not affect the muscles or joints.