It’s crucial for our health and wellbeing, so how can we optimise our sleep?
We sleep for one-third of our lives. On average, that’s 26 years – 9,490 days or 227,760 hours.
It’s something that’s described as the “Swiss army knife of health” as it’s essential for our bodies to function. When we sleep, our bones remineralise, our hormones reset, our brains detoxify, and our moods are regulated.
Without it, our immune system can weaken, the risk for certain cancers are believed to increase, and there can be issues with thinking clearly, amongst other negative health impacts. In the words of neuroscientist Matthew Walker: “When sleep is deficient, there is sickness and disease. And when sleep is abundant, there is vitality and health.”
So why don’t we always give it the attention it deserves?
How long should we be sleeping at night?
We all know the general rule of thumb is eight hours – but more specifically, it should be between seven-and-a-half and nine hours for adults aged between 18 and 64.
But sleep is a personal thing – do you find yourself feeling rested after seven-and-a-half hours, or do you need more?
It all revolves around sleep cycles: 90-minute blocks that cycle through four stages of sleep that all play a function in maintaining your brain’s overall cognitive performance. Optimal bedtimes can be determined based on these cycles and when you need to wake up. For instance, if you’re like me and need to wake at 5:15am to join other commuters on the motorway, bedtime should be at 9:30pm – this allows 15 minutes to fall asleep, and five sleep cycles across seven-and-a-half hours. But if you need nine hours of sleep to feel rested, 8pm is the best time to hit the hay for a total of nine hours’ sleep and six sleep cycles.
The stages of sleep
Within each 90-minute sleep cycle, there are four stages of sleep: N1, N2, N3 and REM (rapid eye movement). Here’s a look at what happens in each:
- NREM Stage N1 (Falling Asleep): This first non-REM stage of sleep helps to get us from wakefulness to sleep, generally within a few minutes. It’s the lightest stage of sleep and is when our heartbeat and breathing slows down and our muscles begin to relax. If we wake during this stage, we may not even recognise that we’ve actually been sleeping. This ‘falling asleep’ stage typically only lasts one to five minutes.
- NREM Stage N2 (Light Sleep): The second non-REM stage of sleep is also considered a light stage – from which you can awake easily – but it comprises the largest percentage of total sleep time. Like N1, breathing and the heartbeat slows further here; there are no eye movements and our body temperature drops.
- NREM Stage N3 (Slow-wave Sleep): The body performs many important health-promoting tasks in this final non-REM stage of sleep – the deepest sleep stage. Your heartbeat and breathing will be at their slowest rate, and there will be no eye movements – the body is fully relaxed. This is when the immune system strengthens and the body undergoes tissue repair and growth, and cell regeneration.
- REM Stage R: Occurring around 90 minutes after we fall asleep, this final stage is when our eye movements become rapid, our breathing and heart rate increase, and brain activity increases – it is also the primary dreaming stage. REM sleep generally makes up 25 per cent of sleep for adults and lasts for around 10 minutes the first time and increases with each cycle – the last cycle can last roughly 30 to 60 minutes.
Preparing for sleep
With sleep working in cycles like this, falling asleep easily at night means you’ll be able to get enough sleep cycles.
But what if you struggle to doze off quickly?
- Feng shui your sleep: Many believe that the furniture arrangement in your bedroom can influence whether or not you have a good night’s sleep. According to the practice of feng shui, our sleep can benefit by having the bed on the opposite side of the doorway, against the wall and not underneath a window. It also suggests avoiding clutter in your sleeping space and keeping bookshelves and mirrors out of direct line of the bed.
- Optimise your bedroom’s temperature: Have you ever tried sleeping in a hot environment and tossed and turned all night? Study shows that increased body and bedroom temperature can impact sleep quality – the majority of people find 20ºC the most comfortable.
- Establish a pre-sleep routine: Relaxation before bedtime has been shown to improve sleep quality. But if watching TV before bed is your form of relaxation, you might want
- to consider switching things up – exposure to blue light, which electronic devices emit in large amounts, negatively impacts your circadian rhythm. It makes your brain think it’s still daytime. Instead, practice some meditation, listen to some calming music, or read a few chapters of the latest book you’ve borrowed from the library.
Take a nap
As well as getting our nightly shut-eye, short naps during the day can also benefit our health. Yes, it might seem counterintuitive to purposefully pause during the day to power down, close your eyes and take a nap. Maybe it brings back memories of being at preschool and taking an after-lunch nap with the class? It certainly does for me. But the research suggests that we could all benefit from regularly taking a nap during the day.
We’ve all done it: not slept enough the night before or stayed up too late, to feel our body screaming and begging for sleep. Adenosine is the chemical in our body that makes us feel this way – the longer a person stays awake, the more this chemical accumulates in the body and the more it accumulates, the more tired you get. Naps can be an effective way to keep adenosine in check, along with a whole host of other benefits:
- Boosted immunity: Naps have been shown to reduce levels of inflammatory cytokines and norepinephrine (a chemical that helps control immunity). On the other hand, sleep deprivation increases the release of pro-inflammatory markers, causing immunodeficiency.
- Improved cognition: They’re known as ‘power naps’ for a reason – a short nap can leave you feeling more alert and improve psychomotor speed and reaction time.
- Better memory: Research has shown that we have an improved ability to learn and retain new information immediately after a nap.
- However, it’s important to not nap for longer than 20 minutes – any longer and it increases the chance of waking too far into the sleep cycle. If you nap for too long, you can wake up feeling groggy and more tired than before. No, thank you!
|How to nap well
So, what are the logistics of taking 10-20 minutes out of your day to nap? Like falling asleep at night, there are many factors that impact our ability to settle in for a short nap, along with the quality of that nap.
Where:
- A cool, quiet and dark environment is optimal – a setting where unwanted interruptions or awakenings are least likely to occur.
- If you’re at work in an office environment, try using earplugs and an eye mask to reduce disruptions during nap time. Is there a quiet space or room you can book for a short time?
- For shift workers, learn to associate the bedroom with sleep and positive emotions (not a space for watching television or studying, for example). Blackout curtains or an eye mask will also help prevent light entering through the closed eyelid, which will stop your body preparing for sleep.
When:
- Early afternoon – or eight hours or more before your bedtime – is recommended. This is when your body experiences a natural circadian dip, and napping later in the day can make it harder to fall asleep at night.
- Some also swear by napping after a cup of coffee – or a ‘nappuccino’, a term coined by author Daniel Pink. The theory behind this is that the body and brain feel the impact of caffeine about 30 minutes after it is consumed. So, having a cup of coffee right before a nap can contribute to your alertness and energy levels after waking up! However, while a ‘nappuccino’ can be beneficial for short naps, it’s a different story for when you plan to go to sleep later in the evening. It’s also advised to avoid alcohol before sleep as it can lead to a restless night and next-day fatigue.
Sleep really is such a crucial part of our overall wellbeing.
Dim the lights, grab your favourite book (or magazine!) to read, and make sure you’re giving yourself the best opportunity to get all the quality slumber you need each night.
