It’s well known that caffeine and sleep aren’t happy bedfellows with countless features warning against a cuppa after lunchtime. But little is known about what caffeine does to your brain once you do drift off.
Now, thanks to a new study out of Canada and with the help of AI (what else?!), we can see that it dials up the complexity of brain signals, which is particularly pronounced if you’re fortunate enough to be under 30.
Put the kettle on, read on and then make a nice warming mug of decaf.
The research, led by Philipp Tholke of University of Montreal, reveals that caffeine affects mechanisms of the brain beyond the ones that leave you tossing and turning. Tholke and his team of scientists monitored 40 healthy adults across two nights – one with caffeine capsules consumed just before bed, another with placebos – and thanks to electroencephalography (ECG) and AI, they revealed dramatic changes in brainwave patterns and neural complexity, more specifically cranking up a person’s state of ‘criticality’.
“Criticality describes a state of the brain that is balanced between order and chaos,” explained one of the co-authors Karim Jerbi. “It’s like an orchestra: too quiet and nothing happens, too chaotic and there’s cacophony. Criticality is the happy medium where brain activity is both organised and flexible.”
Criticality is your friend in the waking hours, helping you focus on foraging safely or making the perfect sloe gin. Unfortunately, this neural state turns into your fiercest foe when darkness falls where it doesn’t just interfere with rest but also impairs recovery. That’s not great as sleep is when your brain reboots its cognitive function (learning, thinking, problem solving…) and when it consolidates memories.
The study also revealed that caffeine had greater impact on the sleep patterns of adults aged 20 and 27 than the subjects involved who were aged between 41 and 58. The researchers suggest this could be down to existing knowledge in this area, which revolves around caffeine inhibiting sleep by blocking adenosine receptors in the brain. Adenosine is a molecule that builds up throughout each day, resulting in fatigue and then sleep. Caffeine’s an adenosine impersonator, so blocks these receptors, leaving you tossing and turning.
What does this mean to your overall health? The scientists suggest further research is required. But until then, stick with that age-old advice of banishing caffeine in the afternoon.
Main image: Getty
