There are times during the day when we find ourselves seriously lacking in the energy department – when we miss those afternoon naps we were made to take as children.
Many people joke about their internal clock, but did you know it does actually exist? Your body has a clock according to which it operates; it’s called your circadian rhythm. Circadian means a naturally occurring 24-hour cycle.
Getting enough sleep
According to the National Sleep Foundation (NSF), adults tend to feel active and lethargic around the same times during the day.
They add that adults have slumps early in the morning, around 03:00 when they’re asleep, and around 14:00, just after lunch.
Those who sleep well and get enough sleep every night may be a lot less affected by these afternoon slumps than those who are sleep deprived.
What is the circadian rhythm?
Over the years, many health professionals, researchers and scientists have studied circadian rhythms and continue to make new discoveries.
Last year, Jeffrey C. Hall, Michael Rosbach and Michael W. Young won the Nobel prize for physiology or medicine for their discoveries of molecular mechanisms that control the circadian rhythm.
Your internal body clock is situated in the brain, more specifically in the hypothalamus, and is scientifically dubbed the suprachiasmatic nucleus (SCN).
Circadian rhythm determines your sleep patterns and is for example affected when you travel across time zones or work with daylight saving time.
The National Institutes of General Medical Science (NIGMS) states that light and darkness also influence your circadian rhythm.
The SCN is positioned above the optic nerves in the brain. It is optimally positioned to receive communication about incoming light, and when there is less light it communicates to the brain that it needs to produce melatonin, a hormone that makes you sleepy.
Age also plays a big part in how your circadian rhythm functions. The NSF states that as you get older, your circadian rhythm changes as the number of hours of sleep you need each night decreases.
Those midday naps
We tend to blame the food we had for lunch for that overpowering desire to have a nap, but there’s more to it than that.
Phyllis Korkki for the New York Times details that because of your circadian rhythm, it’s natural for your body to want to rest after being awake for around seven or eight hours.
She adds that your circadian rhythm converges with another physiological phenomenon – homeostasis – your body’s internal efforts to regulate itself and find a state of equilibrium.
This, coupled with your lunch, causes lethargy because your body is burning more energy trying to regulate itself internally – in addition to digesting that large pasta salad you had for lunch.
The Spanish have the right idea
Having a break or siesta after lunch has been part of Spanish culture since time immemorial, even though some people have moved away from this tradition in recent years. Many other communities have also adopted the idea of a siesta because they have found that a nap improves productivity and alertness for the remainder of the day.
Some US companies, such as Google, Nike and Uber have embraced the concept, and many provide a napping area as a perk.
Naps needn’t be long, though. All your body needs in order to power through the remaining hours of the day is a brief 20- to 30-minute power nap.
Too groggy to be productive
The science of sleep detailed in AsapSCIENCE’s video clip breaks down the four stages of our sleep cycles.
When you sleep for longer than 30 minutes, you tend to feel too groggy to be productive. This is because we prefer to go back to sleep if we’re woken up after entering the third and fourth stages of sleep.
Adding a number of extra hours to your work day to take a longer nap may therefore be counter-productive and have a negative impact on business as well, since we only need the first and second stages of sleep to feel rejuvenated again.