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A long day in the office can leave you empty of energy and overcome with desire for TV and a takeaway. But you’ve been sitting down all day. So why do you feel as tired as your friends who have physical jobs?

Struggling through your list of essential tasks feels ever more gruelling as the clock ticks down for home-time. Worse still is bumping into a colleague on your way out who “just wants a quick minute”. It might seem obvious that you are more likely to make impulsive decisions at the end of a long day, but people often power through anyway.

A recent study that scanned people’s brains at different points in their work day found high-demand tasks which require intense, constant concentration can lead to build-up of a potentially toxic chemical called glutamate. Normally used to send signals from nerve cells, in large quantities glutamate alters the performance of a brain region involved in planning and decision making, the lateral prefrontal cortex (lPFC).

Science has shown time again that mental fatigue has real effects. There are numerous studies which show that court decisions can depend on how fatigued the judge is. For example, after a long day in court, judges are more likely to deny parole (which is considered the safer option). Studies show that clinicians are more likely to prescribe unnecessary antibiotics at the end of a tiring clinical session.

Read the full article on The Conversation website, written by Professor Zoltan Molnar, (Department of Physiology, Anatomy and Genetics, University of Oxford) and Professor Tamas Horvath (Yale University).

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