Revealed: How a 'coffee nap' can help you power through the day - and may even boost your brainpower
- Chin Moi Chow is a sleep and wellbeing researcher at the University of Sydney
- She details a range of studies which have looked into the benefits of coffee naps
- One found combining caffeine with sleep helped improve driving performance
- But drinking too much can produce symptoms of anxiety, irritability, and tremors
Caffeine and napping have something in common.
Both make you feel alert and can enhance your performance, whether that's driving, working or studying.
But some people are convinced that drinking a coffee before a nap gives you an extra zap of energy when you wake up.
How could that be? Is there any evidence to back the power of these so-called coffee naps? Or are we better off getting a good night's sleep?
Here, in a piece for The Conversation, Chin Moi Chow, a sleep and wellbeing researcher from the University of Sydney, explains all.
Some people are convinced that drinking a coffee before a nap gives you an extra zap of energy when you wake up
FEELING SLEEPY?
If you don't get enough sleep, you incur what researchers call a sleep debt.
You can build up a sleep debt without realising it, on purpose or when you feel you have no other option, like to meet work or other deadlines.
Taking a nap is a common way of overcoming your sleepiness and repaying your sleep debt.
Drinking coffee can also help us get through the day. And since the 1990s, researchers have been studying how combining the two might help.
In a 1997 study, 12 sleep-deprived people drank the equivalent of one large cup of brewed coffee and five minutes later had the chance to nap for 15 minutes.
They then did some driving tests in a simulator to check their alertness.
A coffee nap even helped performance if people dozed during their nap time rather than falling into a deeper sleep, a study previously found
Although drinking a coffee (without a nap) helped their driving performance, combining caffeine with a nap (a coffee nap) improved it even further.
People who took a coffee nap were less likely to drift out of their lanes on a two hour monotonous simulated drive.
This was compared to when they just drank a coffee (and had no nap) or when they had a decaffeinated coffee (and without a nap).
A coffee nap even helped performance if people dozed during their nap time rather than falling into a deeper sleep.
A coffee nap also reduced sleepiness once people got up, with people remaining alert for a couple of hours.
However, this early, small study raised many questions.
For instance, we don't know how much coffee the people in the study were used to drinking or if they were what researchers call caffeine-naive and so more likely to experience a greater caffeine 'hit'.
HOW MUCH COFFEE IS SAFE?
While there's evidence that coffee naps work, are they safe?
If we consider caffeine consumption, doses of 300-500mg a day (equivalent to 2-3 large cups of brewed coffee) seem safe, as about 70 per cent of caffeine is converted into paraxanthine, which has no apparent toxic effects.
But drinking too much caffeine (more than 500mg a day) can produce symptoms of nervousness, anxiety, irritability, and body effects of restlessness, palpitation, agitation, chills, tremors and increased urine flow.
Food Standards Australia New Zealand says 95mg of caffeine a day (about two cans of cola) in children aged 5-12, and 210mg a day in adults increase anxiety levels.
It's easy to consume more caffeine than we need. Drinks containing caffeine are on our supermarket shelves and in over-the-counter medicines.
You can keep an eye on your caffeine intake by checking the caffeine content of common drinks, foods and medicines.
If you are drinking too much caffeine and want to stop, withdrawal can cause headache, sleepiness and decreased alertness.
So, given the addictive properties of caffeine, 'caffeine use disorder' has been classified as 'a condition for further study' in the Diagnostic and Statistical Manual of Mental Disorders (DSM-5).
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