Long naps may improve memory in people with high risk of dementia

Date Published: September 11, 2024

Impact of Napping on Dementia Risk: Dr. Caroline Faucher’s study found that long naps improved memory in individuals with a high genetic risk of dementia (APOE4 gene), while people with a lower risk benefitted more from not napping.
Restorative Sleep and Brain Function: The study suggests that long naps might help people at high risk of dementia by providing a second opportunity for the brain’s restorative “washing machine” function, which may not occur effectively during nighttime sleep.
Hope for High-Risk Individuals: With the growing awareness of dementia risk, particularly following Chris Hemsworth’s revelation of having the APOE4 gene, the study offers a potential intervention—long naps of about one hour—as an additional way to reduce dementia risk, alongside diet and exercise.

Sleep and dementia researcher, Dr Caroline Faucher, from HMRI’s Brain Neuromodulation Research Program has identified the impact that napping could have on the memory of those at who could be at high risk of dementia.

In a recent study, she looked at people who have the APOE4 gene, a gene that gives you a high risk of dementia, as well as people with a low polygenic risk score (combined genetic risk) of dementia.

Everyone in the study had similar nighttime sleep habits but their napping habits varied from no naps to short naps and long naps.

Ms Faucher found that long naps were associated with better memory in people with high risk of dementia. For people with a lower risk, not napping could be more beneficial for memory than short naps.

She says, “We think this might be because the brain has a kind of restorative ‘washing machine’ function that happens when we sleep. It seems that in people with high risk of dementia, this cleaning function isn’t happening effectively at night so a long nap in the daytime may give those people another chance for their brain to go through this process.”

In the wake of high-profile celebrity, Chris Hemsworth, finding out he has the APOE4 gene, people are having the blood test to find out if they too have this gene.

Ms Faucher says that in the past, people who discovered that they were at high risk of dementia felt as though there was nothing they could do, beyond all the normal exercise and diet interventions but now, with advances in clinical trials for medications, there is hope.

With a healthy diet and regular physical activity two ways people can reduce the risk of dementia, this new sleep study provides evidence for another thing that people with high risk may be able to do to improve their outcomes – they can take long naps – ideally about one hour per day.