How many sleep cycles should you get through each night?

As studies in sleep science reveal more and more about why and how we sleep, we begin to appreciate just how important the right type of proper, deep sleep is for our daily wellbeing. Technology that allows us to monitor brain activity (electroencephalography, or EEG), during waking and sleeping hours, shows us that neurons in the brain remain active even as we sleep. We might be unconscious, but our brains, as well as bodily functions, go through regular processes through the evening, as we move through the different stages of sleep cycles.

Sleep Scientist, Dr Dale Rae, explains. “A sleep cycle is essentially made up of two sleep phases: Non-Rapid Eye Movement Sleep (NREM) and Rapid Eye Movement Sleep (REM). These are divided into consecutive stages, which we’ll explore in more detail below. To afford ourselves the best quality sleep, we should ideally pass through several, full sleep cycles every night.”

“In simple terms, let’s think of a sleep cycle as a process of four stages that our sleep needs to go through, repetitively and ideally uninterrupted, throughout the night. Each of these stages has an important role to play in our fully recuperative rest. The duration of each stage may change as our sleep progresses.”

The NREM sleep phase comprises the first three stages where the mind and body progressively relax and fall asleep:

First, we begin to doze off (N1), still mildly conscious of any sudden noises that might disturb or awaken us. We should ideally spend less than 5% of sleep time in this stage.
We then progress to a deeper level of subdued sleep (N2), where we are less likely to be woken. The muscles relax as both breathing and the heart rate slows. The body temperature dips slightly. We spend most of our time (50%) in this stage of sleep.
Relaxing even further into the third stage (N3), we achieve a deep, slow-wave sleep. It is more difficult to wake someone up from a fully immersed, N3 sleep stage. The importance of reaching a deep stage of N3 sleep is because this is when the body is thought to do the majority of its restoration. The immune system, for example, trawls the body for damaged and mutated cells and gets rid of them before they cause further harm, and the brain flushes out harmful toxins. We should spend 20% of our time in deep sleep.
Then follows the curious stage of REM sleep. It is called Rapid Eye Movement sleep because this is when brain activity suddenly heightens to near waking levels. At the same time, atonia sets in, where the muscles that affect movement in the body are paralysed, except for the eyes. You may have seen someone fast asleep with their eyes closed, except their eyeballs twitch and move back and forth rapidly. Hence, the REM phase. The brain becomes a sort of night-shift librarian, sorting hurriedly through the cognitive functions of memory, learning, creativity and even emotions. It is during REM sleep that we think we have our most vivid dreams. We should ideally spend 25% of our time in REM sleep.

“Once we have passed through all the NREM and REM stages, we then return to the first NREM stage (N1) of sleep, possibly even waking briefly before we move through the same process again. In other words, we have completed a full sleep cycle and now begin another. The time it takes to go through a full sleep cycle can vary. Generally, a full cycle takes around 90 minutes so that most people typically achieve 4-6 sleep cycles each night.”

“The clue,” says Dr Dale Rae, “is usually symptomatic, when you wake up in the morning, or feel it later on during your working day. If you’re not waking up refreshed and re-energised, or you find your concentration and energy levels dropping significantly during the day, chances are you are not achieving the optimal sleep you need every night. Perhaps your sleep is too short, or perhaps you are not obtaining enough sleep in a specific sleep cycle. For example, spending too much time in N1 and not enough time in N2 will leave a person feeling unrefreshed and yearning for more sleep.”

You may not immediately connect a daytime symptom with a sleep cause until you have begun to monitor and understand regular patterns of disordered sleep. Poor sleep health, as it’s commonly referred to, can sometimes point to a number of reasons for compromised sleep. Let’s explore a few ways to address these.

1. Light sleeping – You may sense that you’re a light sleeper if you are easily disturbed throughout the evening by the slightest noise. It could be a creak of a cupboard, the onset of rain, a dog barking in the distance, or even just an imagined sound. If you’re sleeping, but are easily awoken, you are likely not achieving the depth and levels of what a good, quality night of sleep cycles requires.

What to do? Well, for a start, consider your daily routine. Are you in a particularly demanding, perhaps stressful, job? Are you keeping yourself going on caffeine all day and ‘calming’ yourself with that extra alcoholic drink each night? Are you perhaps having dinner too close to your usual bedtime? You may also be hypersensitive to sound. Perhaps you’ve recently experienced a trauma that keeps prying. Light sleeping is for soldiers on a battlefront. So perhaps there’s a ‘battle’ you’re coping with yourself.

2. Persistent insomnia – You’ve counted sheep in their thousands and all you see is a ceiling. You may find some respite during the night when your levels of exhaustion eventually set in, but you are certainly not getting the ideal sleep cycles to rest and prepare yourself for the next day.

It is a natural, human disposition to need, and want, to sleep regularly each night. Sleeplessness is not a choice. (Even vampires sleep, be it during the day.) Exhaustion will eventually take over and you will simply crash. But then you could just as soon resume your unwanted, nightly vigils.

Without overthinking it, you can often, quite honestly, isolate the causes of insomnia. Excessive stress, be it professional or personal, will keep you up at night. Your food choices, and when you eat your evening meal, may very well be the silliest, most obvious, reason. Over dependence on prescription drugs or excessive alcohol consumption are known enemies of sleep. Instead of the ceiling, take a gentle look at a mirror.

3. Sleep apnoea – Every time you might finally drift off into deep sleep, your body, especially your breathing apparatus, fails you. You wake suddenly in a confused sense of panic because your body has been unduly deprived of air. No oxygen. The lungs cannot function. The heart feels undue pressure. And your brain, thankfully, has sent an emergency wake-up call.

Here are just a few things that might be happening when you’re trying to fall asleep. Sleep apnoea occurs when your upper airway closes or is constricted for a prolonged (more than 10 seconds) period of time. There are many potential causes and a consultation with your doctor may help you find the best solution to treating this underdiagnosed condition.

4. Restless Legs Syndrome (RLS) – You may have felt an uncomfortable itching, crawling, burning, “hard-to-describe" sensation in your legs as you fall asleep. Symptomatic sensations can be mild or severe, and often go away when you stretch or move your legs. There are many possible factors that can cause or aggravate RLS, which can make it difficult to pinpoint the exact, underlying cause.

Persistent RLS will begin to impact the quality of your sleep and overall wellbeing. In some instances, there can be simple lifestyle adjustments to treat RLS, but you would be well advised to discuss possible causes with your medical practitioner.

5. Midnight toilet trips – It’s a thing. And it even has a name – nocturia. Waking up frequently every night to urinate can play havoc with your sleep quality. The full range of sleep cycles, with their consecutive phases, are rudely interrupted.

Should you realise that your toilet trips are becoming more frequent during the evening, consider monitoring and diarising how often you need to go to the toilet. Review any lifestyle changes that might help to alleviate the irritation of nocturia. Are you over-hydrating? Are you drinking caffeine or alcohol too close to bedtime? You might recently have changed your diet. There could also be an underlying medical cause. Again, consult your medical practitioner if you’re not able to take control and self-manage your midnight ablutions.

If you are experiencing persistent sleep interruption, consider talking through your nightly sleep patterns and daytime symptoms with a professional sleep scientist. No matter where you live and sleep in South Africa, you can reach the Sleep Science team at www.sleepscience.co.za and consult remotely.

You’re struggling with interrupted sleep. The first thing you certainly want to review is your mattress. It is so often the most obvious that can be least considered. When last did you upgrade your mattress? Are you sleeping on the right type of comfort and support? How significantly has mattress design and technology improved since you last bought a mattress? You can easily find out at your nearest Dial•a•Bed store. Do a Sleep Station test. Then do the rounds through every conceivable level of comfort and support. Start by browsing www.dialabed.co.za. Make the best of every day. Take your sleep seriously. #SleepForLife.