Mental Fatigue

Cognition is a term used to describe our mental abilities and processes. Simply put, these are the brain-based skills such as thinking and reasoning we use to perform simple and complex tasks.

Your brain gets tired in much the same way that your body does. So, too much cognitive activity over an extended period of time can send your brain into overdrive. This can leave you feeling mentally exhausted, what people sometimes refer to as ‘burnout’. In addition to slowing down your productivity and overall ability to pay attention and focus, it could also lead to more serious health issues.

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Do you feel as though your brain is overloaded? Are you overwhelmed and mentally exhausted most of the time? All of us experience brain drain every so often, for example after a major exam or after preparing a financial report. But if you are consistently and excessively mentally tired, if the feeling never goes away, you could be suffering from mental fatigue.


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Anything that requires a lot of mental energy can make you mentally tired in the short-term. Your brain is wired to deal with short-term stress but it does not react well to persistent, long-term stress.
When you are stressed, your brain activates stress response hormones for pressurised situations that require quick thinking.2 However, if your body’s stress response hormones are activated persistently over a longer period of time, your brain struggles to cope, leaving you feeling mentally fatigued.3


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Often associated with workplace stress, mental fatigue can happen to anyone and can occur if you experience long-term stress in any area of your life. You could be at risk, for example if you are:3

  • Constantly making decisions4
  • Habitually working late5
  • Working in a demanding, high-pressure environment5
  • Experiencing ongoing financial stress5
  • Overcommitting to more tasks than you have time to finish4
  • Juggling work, family, school and friends
  • Dealing with life-changing circumstances such as divorce or the death of a loved one5



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Signs and symptoms vary from person to person and often surface gradually. More importantly, if left unchecked over time mental fatigue can lead to anxiety or depression-like symptoms such as low mood and feeling down.3
Equally, people who suffer from mental fatigue often feel physically exhausted too, which may lead to physical health issues such as insomnia, digestive problems and a weakened immune system. 3, 6



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  • Depression
  • Anxiety
  • Cynicism or pessimism
  • Apathy (feeling of not caring)
  • Detachment
  • Anger / irritability / moodiness
  • Feeling of hopelessness
  • Feeling of dread
  • Lack of motivation
  • Low productivity
  • Difficulty concentrating3


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  • Headaches
  • Problems concentrating
  • Upset stomach
  • Body aches
  • Excessive tiredness
  • Changes in appetite
  • Insomnia
  • Weight gain or weight loss
  • Increased illness, such as colds and flu3


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  • Poor performance at work
  • Social withdrawal or isolation
  • Inability to keep personal or work commitments
  • Low motivation
  • Poor decision-making and judgement
  • Calling in sick to work or school regularly3



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As mental fatigue comes with a wide range of symptoms, diagnosis can be complex in some cases.8 Your doctor may look at your medical history, conduct a physical examination and run some blood tests, urine tests and x-rays to eliminate possible underlying medical causes.8 Fortunately, mental fatigue is treatable and there are various practical things you can do to help ease your symptoms and deal with stress.


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  • Try decluttering your house and workspace – physical clutter can turn into headspace clutter 4
  • Become more organised and get into a routine – start with simple tasks like washing dishes after dinner every night and making your bed every morning when you get up
  • Learn to say ‘no’, take on fewer tasks, delegate and ask for help5
  • Find a balance between doing things efficiently and doing them perfectly – perfectionism can lead to decision paralysis or not being able to make decisions at all4
  • Get 7 to 9 hours of sleep a night – your brain cannot re-energise without regular sleep
  • Before going to bed, make a home and work to-do list for the following day but keep it doable and simple4
  • Take regular breaks throughout the day, take a stroll, get away on a vacation – even if it is for a couple of days a once or twice a year3
  • Learn to relax by practicing meditation or mindfulness – 20 minutes a day can change the way your body responds to stress and decrease your risk of other health issues3, 4
  • Eat a balanced diet with a daily intake of fruit, vegetables, whole grains and lean proteins such as white fish, plain yoghurt, beans and lentils, lean beef and pork, white meat and poultry such as chicken and turkey, and eggs9
  • Exercise – even a brisk walk in your lunch hour is enough
  • Consider taking a natural supplement

Please note: This is educational information only and should not be used for diagnosis. For more information on mental fatigue, consult your healthcare professional.

  1. Sharp Brains. What are Cognitive Abilities and Skills, and How to Boost Them?

Available at: Accessed on 6 March 2019.

  1. Mayo Clinic. Job Burnout: How to spot it and take action.

Available at: Accessed on 6 March 2019

  1. How to Treat and Prevent Mental Exhaustion.

Available at: Accessed on 6 March 2019.

  1. How To Overcome Mental Fatigue, According To An Expert. Available at: Accessed on 6 March 2019.
  2. Medical News Today. Fatigue: Why am I so tired and what can I do about it? Available at: Accessed on 6 March 2019.
  3. University Health Network (UHN). Mental fatigue and what you can do about it. Available at: Accessed on 6 March 2019. Accessed on 6 March 2019.
  4. Symptoms of Mental Fatigue. Available at: Accessed on: 6 March 2019.
  5. Fatigue. Available at: Accessed on 6 March 2019.
  6. Top 13 Lean Protein Foods You Should Eat. Available at: Accessed on 6 March 2019.
  7. Global News. Are you suffering from mental fatigue? Here’s what to look for. Available at: Accessed on 6 March 2019.
  8. Wesnes KA, et al. Psychopharmacol Bull 1997;33(4):677-683.  
  9. Wesnes KA, et al. Psychopharmacology 2000;152(4):353-61.
  10. Scholey AB, Kennedy DO. Hum Psychopharmacol 2002;17(1):35-44.
  11. Kennedy DO, et al. Physiol Behav 2002;75(5):739-51.
  12. Kwiecinski H, et al. Eur J Clin Res 1997;9:59-67.
  13. Brinkley TE, et al. Am J Hypertens 2010;23:528–33.

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