Coffee affects the brain in sleep

Researchers used modern technology – electroencephalography and artificial intelligence – to track how coffee changes brain waves in sleep. It turned out that coffee increases the complexity of brain signals, making its state similar to a balance between order and chaos – a kind of ‘golden mean’ for brain function.

This ‘critical’ mode helps to quickly process information and make decisions during the day, but at night it prevents the brain from relaxing and fully recovering. This effect is especially noticeable in young people – their brains are more sensitive to caffeine.

The experiment involved 40 adults who slept under the control of scientists on two nights: once after taking caffeine, and in the other – a placebo. The brain ‘under coffee’ showed fewer deep waves, important for rest, and more wakeful rhythms, suggesting that quality sleep was impaired.

Interestingly, the effect was weaker in people over 40 – as we age, the brain loses some of the receptors that caffeine acts on. This explains why in the young, coffee can take longer to interfere with sleep and recovery.

Now scientists want to understand how these changes affect memory, concentration and general health. In the meantime, it’s worth considering whether it might be worth reducing your caffeine intake, especially before bed, to keep your mind strong and clear.