"The first stage of sleep is a hybrid state between wake and sleep, potentially providing the best of the two worlds for creativity," says Delphine Oudiette, the study's author. "It is associated with rich, spontaneous, dream-like experiences (called hypnagogia) which could be what is causing the idea generation."
Another study from China, published in General Psychiatry, found that an afternoon nap improved mental flexibility and led to better locational awareness, verbal fluency and working memory in older people.
For many, napping is also a fast track to feeling a whole lot happier. Lorraine Marsh, 38, co-founder of jewellery business The Diamond Setter in Royal Tunbridge Wells, is a committed advocate of the power nap.
"My dad used to run a construction business and every afternoon, he would come home for lunch and a nap," she says. "That might have been my first influence. Now I'm running my own business, I sometimes have fairly sleepless nights and if I allow myself a half-hour afternoon nap, I am much more energised for the rest of the day."
Not a fan of the uncomfortable chair snooze, Lorraine adds: "I need my bed for a nap. I do change to comfortable clothing, loungewear but not pyjamas. My best naps are between 2pm and 3pm."
Unsurprisingly, her nap habit isn't daily. "I have to be at my jewellery studio most days, so I can only do this when I am working from home," she explains. "That way, I can continue with work afterwards and I'm even up for exercise later in the evening."
She's far from alone in her nap habit.
"Napping is very common – and increasingly so as we get older," says Dr Deborah Lee, sleep expert for Dr Fox Online Pharmacy. "In one study, 22 per cent of adults admitted to napping at least two days a week, but for over-75s this rose to 53 per cent."
However, a study that recently made headlines, led by UC San Francisco and Harvard Medical School, revealed that napping could also be a precursor to Alzheimer's Disease and other dementias. After diagnosis, they also found that the frequency of napping "accelerates rapidly".
The research backs up a 2019 study that discovered that older men who napped for longer than two hours daily had a greater chance of cognitive impairment as they age.
Napping v irritability
But it's not all bad news by any means. "Many studies show that napping is good for brain function," says Dr Lee. "In a 2021 review which included 11 laboratory-based studies, napping was shown to improve cognitive function and alertness, and these improvements lasted for two hours after waking. "
In a further study from Harvard, participants who napped regularly showed a 37 per cent risk reduction in dying from cardiovascular diseases, partly because napping helps to relieve stress. For men, the difference was even starker, with male nappers reducing their risk of heart problems by up to 64 per cent. One Nasa study even found that a 40-minute nap improved astronauts' alertness by up to 100 per cent and had a dramatically positive effect on performance.
"Napping is also the perfect antidote to irritability caused by fatigue," says Charlie Morley, author of Wake Up to Sleep.
"The amygdala is the part of the brain that deals with threat and irritation," he explains. "After a sleepless night, it becomes a huge 60 per cent more reactive – this is why you're so snappy when you're tired. Research has shown that a short nap can greatly reduce that reactivity."
But how long should we really be napping during the day? Nap-haters like me cite grogginess and disorientation and feel it ruins their sleep that night.
"Your nap should finish at least six hours before you intend to go to bed and should be no more than an hour, maximum," says Morley. "Even a 20-minute rest without sleeping can have brilliantly rejuvenating effects."
Dr Verena Senn, a sleep expert at Emma Sleep, also believes the ideal nap should last just 20 minutes: "That will give you an extra boost of alertness without succumbing to the grogginess often associated with oversleeping."
"Another feature of a good nap is that it is done in the right environment," says Senn. So forget the post-lunch whistling snooze in the armchair. "The best place for your naps is your bed," she adds. "Napping elsewhere, such as the sofa, will not offer the same support for your back, neck and head."
It's all too easy to have a nap that leaves you feeling worse, according to the experts. "A 'bad' nap is a nap that is too long, or taken too late in the day," says Dr Lee.
Lisa Artis, deputy CEO of The Sleep Council, adds: "Naps can give you as much energy as two cups of strong coffee, but the effects are longer lasting." However, she warns: "If you find yourself needing a nap most days, and a long nap at that, then chances are you aren't sleeping very well so it's important to look at your sleeping patterns and consider consulting a GP as there could be an underlying medical condition."
I don't usually feel the need – but now and then it would be lovely to shut the world off for a minute or two. Armed with the knowledge that just one minute of sleep can make a difference, I'm prepared to try again – and I'll wear headphones and shut the dog out of the room.
Three steps to the perfect nap
1. Plan your nap, so you take it at lunchtime or early afternoon, in a quiet, private environment.
2. Set your alarm so you don't sleep any longer than 30 minutes – 20 minutes is advised.
3. After your nap, wake up promptly and do something invigorating such as washing your face in cold water so you are fully awake. - Dr Deborah Lee, sleep expert for Dr Fox Online Pharmacy