🌙 Insomnia: Why Your Brain Refuses to Sleep?

For many people, turning off the brain at nightfall is impossible, despite very real fatigue. Australian research offers an explanation for this enigma by implicating a misalignment of our biological clock.

Insomnia affects approximately one in ten people, and up to one third of older adults. A large number of them describe a mind that races or becomes hyperactive at bedtime. To examine this phenomenon, scientists sought to find out if this nocturnal mental alertness could be linked to a disruption of our biological rhythms.


To test this hypothesis, the team observed 32 older participants, half of whom had insomnia. All stayed awake for 24 hours in a controlled environment without external time cues. Every hour, they described the nature of their thoughts, which allowed for mapping mental activity throughout the day.

The observations, published in Sleep Medicine, indicate that both good sleepers and insomniacs show regular fluctuations in cognitive activity. However, in people with sleep disorders, the peak of this activity occurs with a six and a half-hour shift. Their brain thus maintains a daytime mode of thinking during the night.

According to Professor Kurt Lushington from the University of South Australia, sleep isn't just about closing your eyes. It requires the brain to detach from goal-oriented thoughts and emotions. In insomniacs, this decoupling is weaker and delayed, likely due to circadian rhythm abnormalities.

Consequently, the internal signal to switch to 'sleep mode' in the evening is weaker. The biological clock, instead of promoting calm, maintains a state of mental alertness late into the night. These elements help explain why it is so hard for some to 'switch off' the mind.

Current treatments often focus on behavioral strategies. But integrating circadian and cognitive factors could offer better-tailored solutions for affected individuals. This work highlights the importance of considering the internal clock in managing sleep disorders.