Everyone knows what it feels like after you have had an excellent night’s rest. Similarly, we know the other feeling of wishing you had a better night. (However, we often respond to anyone who asks that we had a good one). Thanks to several reports and research studies that have been educated on sleep. We can better understand rest. On the other hand, this understanding allows us to sleep better.
The subject of good sleep hygiene must consider the quality and the quantity of our sleep. As for the amount, adults aged 18 and above are expected to do 7 to 9 hours. The other teenage years can spend 8 to 10 hours by recommendation. The school-age children aged between 6 and 13 need 9 to 11 hours. As for pre-school children, they need between 10 to 13 hours. However, newborns under three can freely sleep for 14 to 17 hours.
Regarding sleep quality, we need to dig deeper into the biological aspect of sleep for improved sleep hygiene. Hence this article will describe each stage so we can all maximize it. Let us begin with the stages in the sleep cycle.
Stages of the Sleep Cycle for Better Sleep Hygiene
There are five known stages of sleep in a typical sleep cycle, and this understanding can help us achieve more effective sleep hygiene. This classification is based on the brain’s and body’s activities and characteristics during sleep. REM sleep stands out of the five stages, while the other four are grouped as the non-REM sleep stage.
A straightforward way to differentiate between the different stages of sleep is by using the electroencephalogram (EEG), which measures the brainwave amplitudes and frequencies. The EEG can also measure biological rhythms such as muscle movements (EMG) and eye movements (EOG) during sleep.
The Non-REM Sleep Stages
Stage 1 stage of the sleep cycle is the entry point and the lightest stage of sleep. Meanwhile, the EEG brain frequency can be slightly slower than the period when you are fully awake. At this stage, you can experience some muscle tone presence alongside the skeletal muscles. Also, this stage is characterized by a regular heartbeat rate.
In stage 2 of the sleep cycle, the person from stage 1 has entered a deeper part of the sleep. In stage 2, the sleeper is now less capable of waking up and experiences some characteristics of sleep spindles. We can also observe “saw tooth waves.”
Stages 3 and 4
Both stages 3 and 4 signify the deep sleep stage, which is the progress made from stage 2, which is only relatively deeper than stage 1. This stage is known as the “Slow Wave Sleep,” SWS, or the delta sleep. During the deep sleep stages, we notice a much slower frequency on the EEG while having high amplitude signals, known as delta waves.
Beyond what the sleeper experiences at stage 2, it is more difficult for the sleeper to wake from sleep now. Research even showed that when a noise of over 100 decibels is applied to one in a deep sleep, it may not awaken the sleeper at this stage. Meanwhile, as a person advances in age, they tend to spend less time in the deep or slow-wave stage of sleep and more time at stage 2.
Perhaps, that explains why adults are more accessible to call out of sleep than younger ones. Furthermore, we refer to the SWS as deep sleep because they signify the most profound experience of sleep one may have in an NREM stage. Moreover, stage 3 shows arousal thresholds that make it more difficult to wake someone in that stage. And if you succeed in waking a person up from stage 3, the person may feel groggy.
In addition, the mental performance of the person may be slightly impaired. Another research showed that this impairment might take up to 30 minutes when we apply some cognitive tests. This characteristic feature differentiates this stage from the other steps, and the experience is known as Sleep Inertia.
In the case of sleep deprivation, there may be a sharp rebound from the SWS, proving that there is more need for that stage for better sleep hygiene. In earlier reports of this stage, it was termed a brain quiescence. But later, we discover that it is a very active mind-brain state. Further research on brain activity during non-REM sleep stages shows that the most recent waking experience affects brain activity.
The REM Sleep Stage
The final stage of sleep, or what we refer to as the REM sleep stage, is characteristic of dreaming. Dreaming is the difference between this stage and the other stages. Meanwhile, the EEG shows a frequency that is close to being awake. In other words, one can assume that the mind is fully sharp but only in another ‘world.’ The sleeper’s experience is as though everything is accurate. However, at this stage, the skeletal muscles are atonic, which means they do not move. Then, the sleeping at this stage is irregular and erratic while the heartbeat dramatically increases. Some theories even opined that the atonic muscles at this stage are necessary to protect individuals having a dream at the REM stage from injury.
Sleep Spindles and K-Complexes
At the Non-REM sleep stages, the sleeper experiences spindle activity either at the start or the end of the stage. This stage is automatic for sleepers as soon as they get to stage 2 of their sleep. Spindles also have different lengths or durations, but one can increase the activities of other parts of the brain’s frontal lobe with different frequencies. Further research is ongoing at this stage.
On the other hand, K-complexes are similar to spindles and exclusive to NREM sleep stages. However, they are characterized by a single long delta wave that lasts only one second. Sleepers experience this stage by automatic prompt but can also be induced momentarily by sudden events. For instance, when someone knocks on a person’s door at the NREM stage, a K-complex may occur.
Finally, sleep hygiene is not achievable until we have a hold on the sleep understanding. Moreover, each stage’s experiences and expectations can also help us understand how to make the best of each. In all, you can master your sleep hygiene for longer and healthier life.