Short daytime naps good for brain health, research suggests

Taking regular, short daily naps is good for our brain to help reduce shrinkage, according to University College London research.

The team showed nappers’ brains were 15 cubic centimetres (0.9 cubic inches) larger — equivalent to delaying ageing by between three and six years.

Scientists recommend a short snooze, no more than 30 minutes, which can improve the brain’s ability to learn, while previous research has suggested long naps could be an early symptom of Alzheimer’s disease.

Though the researchers noted daytime napping is hard in many careers and mostly frowned upon in workplace culture.

The team say they have found evidence to suggest napping may help to protect against brain shrinkage, which is of interest.

Brain shrinkage, a process that occurs with age, is accelerated in people with cognitive problems and neurodegenerative diseases, with some research suggesting this may be related to sleep problems.

“We are suggesting that everybody could potentially experience some benefit from napping,” Dr Victoria Garfield told the BBC. 

She described the findings as ‘quite novel and quite exciting’.

Napping has been shown to be critical for development in babies, becoming less common as we age and then goes through a resurgence in popularity after retirement — with 27% of people over 65 reporting having a daytime nap.

Dr Garfield says advice to nap is ‘something quite easy’ to do in comparison to weight loss or exercise which can be ‘difficult for a lot of people’.

Our brains naturally shrink with age, but scientists are yet to prove whether short naps could help prevent diseases like Altzheimer’s, as extra research is needed.

Overall brain health is important in protecting against dementia — a condition linked to disturbed sleep.

According to researchers, poor sleep is damaging to the brain and over time, it can cause inflammation and affect the connections between brain cells.

“Thus, regular napping could protect against neurodegeneration by compensating for deficient sleep,” researcher Valentina Paz said.

However, Dr Garfield is not planning on getting some shut eye while at work. She said she prefers other ways of looking after her brain, saying: “Honestly, I would rather spend 30 minutes exercising than napping, I’ll probably try and recommend that my mum does it.”

The UCL research team used a large-scale natural experiment based on DNA. Previous studies have identified 97 snippets of our genetic coding that can either make us more likely to take naps or rather ‘power on’ through the day.

Writing in the journal Sleep Health, researchers at UCL and the University of the Republic in Uruguay report how they drew on data from the UK Biobank study that has collated genetic, lifestyle and health information from 500,000 people aged 40 to 69.

They used data from 35,080 Biobank participants to study whether a combination of genetic variants that have previously been associated with self-reported habitual daytime napping are also linked to brain volume, including other areas of brain health.

Results showed a 15 cubic centimetre difference — equivalent to 2.6 to 6.5 years of ageing, with total brain volumes used in the study measuring around 1,480 cubic centimetres.

“I enjoy short naps on the weekends and this study has convinced me that I shouldn’t feel lazy napping, it may even be protecting my brain,” Professor Tara Spires-Jones, from the University of Edinburgh and the president of the British Neuroscience Association, told the BBC.

She said the study showed a ‘small but significant increase in brain volume’ which ‘adds to the data indicating that sleep is important for brain health’.

The researchers did not directly study having a longer sleep in the middle of the day, but said the science pointed towards having 30 minutes or less.