A short afternoon nap can physically reorganise the brain, improving its capacity to learn, according to new research published in the journal NeuroImage.
A study conducted by researchers at the Medical Center – University of Freiburg and the University of Geneva has found that a brief sleep period is sufficient to reset the connections between nerve cells, clearing “space” for new information to be stored. Until now, scientists believed that this vital restorative process — known as a “synaptic reset” — only occurred during a full night’s sleep.
“Our results suggest that even short periods of sleep enhance the brain’s capacity to encode new information,” says study leader Professor Christoph Nissen, formerly of the University of Freiburg and now at the University of Geneva.
The saturation point
The study addresses a fundamental limit of human cognition: synaptic saturation. During the day, the brain is constantly processing new impressions and information, which strengthens the connections (synapses) between nerve cells. While this strengthening is the basis of learning, it eventually reaches a point of saturation, at which the brain cannot absorb any more.
The researchers found that sleep acts as a regulator, downscaling this excessive activity without deleting important memories.
“The study shows that this ‘synaptic reset’ can happen with just an afternoon nap, clearing space for new memories to form,” says Nissen.
Measuring the reset
To test the theory, the team examined 20 healthy young adults who either napped or stayed awake on two separate afternoons. The naps lasted an average of 45 minutes.
Because it is not possible to measure synapses directly in living humans, the researchers employed non-invasive techniques, including transcranial magnetic stimulation (TMS) and EEG measurements. These tools allowed them to assess the excitability and flexibility of the brain’s neural networks.
The results were clear: after a nap, the overall strength of synaptic connections was reduced — indicating that the “reset” had occurred — while the brain’s ability to form new connections was significantly improved compared to those who stayed awake.
“A short nap can help you think more clearly and continue working with concentration,” says Professor Kai Spiegelhalder, head of Psychiatric Sleep Research at the University Medical Center Freiburg.
Implications for high-performance roles
The findings provide a biological justification for the “power nap,” particularly in professions that require sustained high-level performance, such as professional sports, music, and safety-critical industries.
However, the team cautioned that while naps are beneficial for healthy individuals, those with chronic insomnia should be cautious. The researchers noted that sleeping pills can disrupt these natural recovery processes and lead to dependence, recommending cognitive behavioural therapy (CBT-I) over medication for sleep disorders.
