Nap frequency might help to explain the controversial findings regarding the association between napping and CVD.

Regular Napping Might Protect Against Some Aging Brain Shrinkage Interview with:

Valentina Paz, M.Sc Ph.D.  Student Research and teaching assistant
Universidad de la República, UruguayHon. Research Assistant
MRC Unit for Lifelong Health & Ageing 
Department of Population Science & Experimental Medicine
Institute of Cardiovascular Science
University College London

Valentina Paz

Valentina Paz, M.Sc Ph.D.  Student
Research and teaching assistant
Universidad de la República, UruguayHon. Research AssistantMRC Unit for Lifelong Health & Ageing Department of Population Science & Experimental MedicineInstitute of Cardiovascular ScienceUniversity College London What is the background for this study?

Response: Prior research indicates that napping can enhance performance on specific cognitive tasks. However, some authors argue that the advantages derived from napping may vary between individuals who frequently have a nap and those who never naps. Furthermore, it remains to be seen whether habitual daytime napping has a positive or negative impact on cognition and the association between napping and brain volume is not well characterized.

Therefore, our study aimed to examine whether the association between genetic liability to daytime napping, cognitive function, and brain volumes might be causal using a technic called Mendelian randomization and the UK What are the main findings? Is ‘too much napping’ a bad thing?

Response:  Our main finding was a modest association between genetic liability to self-reported habitual daytime napping and larger total brain volume. Assessments of brain volume have been employed as proxies of neurodegeneration. Brain volume reduction occurs naturally throughout an individual’s life; however, this decline is accelerated in individuals experiencing cognitive decline and neurodegenerative disorders. It is proposed that sleep deficits may contribute to these structural changes.

Thus, our main result could suggest that engaging in regular napping provides some protection against neurodegeneration by compensating for inadequate sleep. What should readers take away from your report?

Response: Based on previous work, which suggests a decline in whole brain volume ranging between 0.2% and 0.5% per year, our finding of a larger total brain volume (15.8 cm3, equivalent to a difference of approximately 1.3%) roughly equals 2.6-6.5 years of age difference. This difference approximately equates to the difference in brain volume observed between individuals with normal cognitive function and those exhibiting mild cognitive impairment. Understanding this difference has important clinical implications for mitigating age-related cognitive impairments, particularly if these findings can be generalizable to the whole population. What recommendations do you have for future research as a results of this study?

Response: Future studies should focus on the associations between napping and other cognitive abilities (like alertness) and brain regions and replicate these findings in different ancestries and age groups. Moreover, we only analyzed the frequency of napping; thus, future work should study the length and timing of daytime napping. Is there anything else you would like to add? Any disclosures?

Response: I will like to add that this project was a collaborative work between Universidad de la República (Uruguay), Massachusetts General Hospital, Harvard Medical School (United States) and University College London (United Kingdom).

No disclosures. 

Citation: Valentina Paz, Hassan S. Dashti, Victoria Garfield,
Is there an association between daytime napping, cognitive function, and brain volume? A Mendelian randomization study in the UK Biobank,

Sleep Health, 2023,ISSN 2352-7218,

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Last Updated on July 2, 2023 by Marie Benz