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work fatigue exhaustion after work Work affecting mental health how to work more efficient signs of exhaustion from work

Work fatigue at a desk job- How to work more efficiently

Published Nov 7, 2022 | Updated Feb 8, 2024

Working a job that is mentally stimulating can be rewarding. A study of 100,000 people found that those working mentally stimulating jobs had better brain connections and a lower risk of dementia than those with simpler jobs [1]. Jobs that challenge you the right way in the right amount can benefit your brain. But what happens when this is overdone? Working long hours in mentally demanding jobs with low resources can lead to cognitive fatigue. You might experience exhaustion after work at a desk job without doing any physical labour. Here is why this happens.

Your brain during a demanding workday

Let’s assume you spend 8 hours behind a desk, making important decisions every hour. Your brain helps you make these decisions by sending signals using chemicals. Glutamate is the major excitatory brain chemical that relays these messages between different areas of the brain. It does this by activating brain cells. It is involved in learning, memory formation, and forming new connections [2]. Due to the powerful nature of glutamate, it must always be maintained at an optimal level. The brain balances surplus glutamate levels by increasing a relaxing brain chemical called GABA [3]. This way the intricate balance of glutamate and GABA is maintained. 

When you work on difficult tasks for long hours, your brain pumps up the glutamate to help you accomplish your tasks. If this isn't balanced by intermittently increasing GABA, excessive glutamate accumulates in the brain. Researcher Antonius Wiehler and his team at the Paris Brain Institute measured the levels of glutamate among participants who spent 6.5 hours doing challenging tasks. These individuals had a higher build-up of glutamate compared to those who did simple tasks [4].

Desk work affecting mental health is a concern because the build-up of glutamate was found in the decision-making area of the brain. The brain tries to handle this cognitive fatigue by steering you towards making inefficient decisions that are easier and less mentally demanding [4]. This is a protective mechanism to prevent continued glutamate accumulation.

How to stay focused during long workdays?

One of the signs of exhaustion from work is struggling to make strategic work decisions, despite being qualified. Bringing back the glutamate-GABA balance is one way to stay focused throughout the workday. Since there is little you can do to modify work challenges, increasing GABA levels can help improve efficiency. Below are evidenced ways of increasing GABA levels:

Supplement with L-theanine: L-theanine is a nutrient found in green tea which increases the relative concentration of GABA. It promotes relaxation without sedation within 30 minutes of intake [5][6]. A review of 14 studies reported that regular intake of 200-400mg L-theanine (13-26 cups of tea) for 2 weeks reduced stress and had a calming effect [7]. A high dose that is effective is easier to achieve through L-theanine supplementation, than drinking many cups of tea. Taking L-theanine during your 10 mins afternoon break is a good way to balance your brain chemicals and help your brain to make better decisions. Brain feed’s L-theanine is naturally extracted from green tea and provides 250mg L-theanine from only £15.99. Additional 15% off your 1st order using code NEW15

Practice yoga: Yoga is a type of meditation that involves focused breathing and mindfulness. It can be an effective way of using long lunch breaks at work. Based on how experienced you are, practising yoga for an hour three times a week is shown to increase GABA levels by 13%-27% [8]. Those who performed meditation regularly were found to have a better glutamate-GABA balance than those who didn’t [9].

Take planned breaks: In addition to prioritising the most important decision-making tasks at the start of the day, planned breaks throughout the workday can result in better outcomes. A review of 22 studies found that 10 minute breaks serve as recovery tools [10]. A 10-minute break to stretch or take a short walk can increase positivity and decrease fatigue. Using that break to connect with family and friends was shown to increase vitality. Even a 40-second break from a demanding task can help refocus and improve attention [10]. Breaks can serve as an easy and effective tool to improve work efficiency. 

The good news is that the brain can clear excess glutamate during sleep, which is why, despite a long day at work, you wake up rejuvenated after a good night’s sleep, ready to take on the next challenge.


  1. Kivimäki, M. et al. (2021). Cognitive stimulation in the workplace, plasma proteins, and risk of dementia: three analyses of population cohort studies. BMJ (Clinical research ed.)374, n1804.
  2. Caccia, C. et al. (2019). The Role of Glutamate in the Healthy Brain and in the Pathophysiology of Parkinson’s Disease. European Neurological Review. 14(Suppl.2):2–12
  3. Sears, S.M. and Hewett, S.J. (2021). Influence of glutamate and GABA transport on brain excitatory/inhibitory balance. Experimental Biology and Medicine (Maywood, N.J.), [online] 246(9), pp.1069–1083.
  4. Wiehler, A. et al. (2022). A neuro-metabolic account of why daylong cognitive work alters the control of economic decisions. Current Biology, [online] 32(16), pp.3564-3575.e5.
  5. White, D. et al. (2016). Anti-Stress, Behavioural and Magnetoencephalography Effects of an l-Theanine-Based Nutrient Drink: A Randomised, Double-Blind, Placebo-Controlled, Crossover Trial. Nutrients, [online] 8(1), p.53.
  6. Nobre, A. et al. (2008). L-theanine, a natural constituent in tea, and its effect on mental state. Asia Pac J Clin Nutr, [online] 17(S1), pp.167–168. 
  7. Lopes Sakamoto, F. et al. (2019). Psychotropic effects of L-theanine and its clinical properties: From the management of anxiety and stress to a potential use in schizophrenia. Pharmacological Research, 147, p.104395.
  8. Streeter, C.C. et al. (2010). Effects of Yoga Versus Walking on Mood, Anxiety, and Brain GABA Levels: A Randomized Controlled MRS Study. The Journal of Alternative and Complementary Medicine, 16(11), pp.1145–1152.
  9. Fayed, N. et al. (2013). Brain Changes in Long-Term Zen Meditators Using Proton Magnetic Resonance Spectroscopy and Diffusion Tensor Imaging: A Controlled Study. PLoS ONE, 8(3), p.e58476.
  10. Albulescu, P. et al. (2022). ‘Give me a break!’ A systematic review and meta-analysis on the efficacy of micro-breaks for increasing well-being and performance. PLOS ONE, 17(8), p.e0272460.

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