You may not need to feel guilty about that afternoon nap
A new study has found that some people could be more prone to napping because of their genetics.
The world is divided into two types of people: those that can nap and those that can't. Some swear by it, finding it easy to nod off and recharge their batteries ahead of the rest of the day. Others can't think of anything worse than waking up feeling groggy and bleary eyed.
But if you love nothing more than catching forty winks in the afternoon, then it may not be your fault or anything to do with accusations of laziness. According to new research, you may just have been born with the need to nap.
Scientists at Massachusetts General Hospital (MGH) analysed the genetic information from 452,633 people and participants were asked how many times they napped during the day. They were given three choices of answers - never/rarely, sometimes or usually - and some were also asked to wear an activity monitor, or accelerometers, to monitor their naps, giving "an extra layer of confidence" that the study's results were real and not an artefact.
One of the study's leads, Dr Hassan Dashti, said: "Napping is somewhat controversial. It was important to try to disentangle the biological pathways that contribute to why we nap."
The findings were published in the journal
Nature Communications.
Researchers carried out an A genome-wide association study (GWAS) to determine genetic variations associated with napping.
The study identified 123 regions in the human genome associated with sleeping during the day and a large number of these regions were already associated with napping.
Whilst the research found that two of the main reasons for people napping more were "disrupted sleep" and "early morning awakening", it also found a third group of people who simply need more sleep, known as sleep propensity.
Dr Dashti said: "This tells us that daytime napping is biologically driven and not just an environmental or behavioural choice."
Some of the genetic traits identified were also linked to health concerns, including obesity and high blood pressure. Meanwhile, several of the napping gene variants were associated with orexin, a neuropeptide, linked to wakefulness.
Co-author graduate student Iyas Daghlas from Harvard Medical School said: "This pathway is known to be involved in rare sleep disorders like narcolepsy, but our findings show that smaller perturbations in the pathway can explain why some people nap more than others."
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