Genes play a role in how often, if at all, people take daytime naps, research has revealed.
Identifying dozens of genetic regions associated with napping, a team of researchers from Massachusetts General Hospital (MGH) and the University of Murcia in Spain conducted the largest study of its kind. Additionally, they discovered genetic links to cardiometabolic health.
“Napping is somewhat controversial,” said Hassan Saeed Dashti, PhD, RD, of the MGH Center for Genomic Medicine, co-lead author of the report. Dashti noted that some countries (such as Spain) which featured daytime napping in their culture now discourage it. Conversely, some companies in the United States now promote napping as a productivity. “It was important to try to disentangle the biological pathways that contribute to why we nap,” said Dashti.
In a Genome-Wide Association Study, the MGH researchers used genomic data obtained from the UK Biobank, which holds the genomes of 452 633 people. They replicated their findings using data from the company 23andMe which has obtained data from 541 333 people. The participants had rated their daytime napping habits, and a subset wore accelerometers to provide objective verification of resting behaviour. A number of the genes analysed were also already known to be associated with sleep.
The GWAS identified 123 genetic areas associated with napping. On further investigation, the researchers identified three factors which promote napping:
Sleep propensity: Some people require more sleep than others.
Disrupted sleep: Daytime napping can make up for poor sleep the previous night.
Early morning awakening: People who wake up too early can ‘get back’ some sleeping` time.
“This tells us that daytime napping is biologically driven and not just an environmental or behavioural choice,” said Dashti. Some of these subtypes were linked to cardiometabolic health concerns, such as waist circumference.
“Future work may help to develop personalised recommendations for siesta,” concluded Garaulet.
A number of the genes related to napping were already associated with orexin, a neuropeptide involved in wakefulness, as well as a number of other areas such as mood and feeding behaviour. This pathway is known to be associated with narcolepsy, but the findings suggested that smaller perturbations seem to be associated with napping.
Source: Medical Xpress
Journal information: Dashti, H.S., Daghlas, I., Lane, J.M. et al. Genetic determinants of daytime napping and effects on cardiometabolic health. Nat Commun 12, 900 (2021). doi.org/10.1038/s41467-020-20585-3 , www.nature.com/articles/s41467-020-20585-3
