How much energy does thinking use? © Getty Images

How much energy does thinking use?

Whether you are exercising your body or your brain, you're going to need more energy. So just how much energy do you need when deep in thought?

Asked by: Anonymous

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Your brain, in general, accounts for about 20 per cent of your total energy requirements. That’s an average of 400-500 calories a day, but it varies according to how hard your brain is working. Under deep anaesthesia, your brain still needs about 150 calories a day. But experiments with rats have shown that just moving from being deeply anaesthetised to conscious but anaesthetised increases energy demands by 50 per cent. When we are awake, a large proportion of brain function is taken up simply with controlling muscles and processing sensory input. Experiments to measure the impact of abstract problem solving on the brain’s metabolic requirements have shown that it also depends on your IQ. The more intelligent you are, the more energy you expend on a problem that is subjectively hard for you.


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