How Sleep Changes Throughout Our Lives
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Sleep can be challenging on some nights and there may be many reasons why we can’t fall asleep. But, when sleeplessness strikes, there are some hacks you can try. Let’s explore how sleep changes at every age throughout our lives!
You may think of sleep as a single experience: we go to sleep, get some rest, wake up, live out our day, and repeat. However, sleep is a lot more complex than that and our experience of it is constantly changing.
When we sleep, how much we sleep, and the quality of sleep we get transforms throughout our lives. In this article, we’ll look at how our changing biology affects our sleep over time.
The Importance of the Circadian Rhythm
The circadian rhythm is our body’s biological clock that operates on a 24-hour cycle. This cycle is controlled by a tiny part of the brain that’s able to influence various different biological processes. The circacian rhythm’s greatest power, however, is to determine when we’re awake and when we’re asleep.
Our biological clock signals our body that it’s time to slow down and sleep by releasing melatonin. You may have already heard of melatonin, which is the hormone that tells our bodies to prepare for sleep and makes us feel tired.
The setting of the sun and absence of light also signals the oncoming night and results in the release of melatonin, which usually urges us to sleep within about 2 hours. Melatonin levels decline during the night, allowing us to feel refreshed and wide awake by the time morning returns.
Circadian rhythms vary slightly between people, creating distinctions we know as “early birds,” or, “night owls.” More significantly, our circadian rhythm changes as we age, determining when and how much we sleep.
REM vs. NREM Sleep
In the early 1950s, it was discovered that sleep is not a uniform experience and instead exists in phases. We have two different phases of sleep: rapid eye movement sleep and non-rapid eye movement sleep, or as you may know them: REM and NREM sleep. REM sleep is also called “dream sleep,” as our brain is a lot more active and we tend to experience dreams in this phase. During NREM sleep on the other hand, brain activity is calmer and typically no dreams occur. REM sleep is also a much lighter sleep compared to NREM, meaning you can be more easily awoken from it. Have you ever been woken up from your afternoon nap by the slightest sound, maybe a door closing or a kettle boiling? And yet on other occasions, you’ll find yourself waking up to your family members telling you that they’ve been trying to get you up for the past 10 minutes. This may be due to the differences in the sleep phases that you were in at those times.
These two phases don’t simply occur as two blocks in our sleep. Instead, we cycle through sleep phases approximately every 1.5 hours. Moreover, the proportion of REM to NREM sleep we get in a night’s sleep changes throughout our lives.
Sleep in Early Childhood
A child’s sleeping pattern changes drastically within the first few years of life. Every parent will know that, when first born, babies don’t often sleep through the night. Rather, they have short and frequent phases of sleep throughout the day and night. There are several reasons for this and one of them is that their internal biological clock hasn’t fully developed and doesn’t yet have a firm concept of the 24-hour cycle based on night and day. The good news is that this period of highly inconvenient sleeping patterns doesn’t last long.
As our internal clock tunes into the regular signals of day and night and starts to adjust our biological processes, these sleep phases tend to stabilize. Three to four month old babies usually sleep through most of the night with a few naps during the day. Around age four, daily sleep often reduces to two phases: one long phase at night and a shorter nap during the day. By late childhood, children usually no longer require a daytime nap.
Sleep in Teenage Years & Early Adulthood
Do you remember when you were a teenager and it seemed impossible to get yourself out of bed around lunch time? When staying up until 2-3:00 am was easy and required no effort whatsoever? As a parent, you may experience the challenging task of trying to get your teenager out of bed in time for a family breakfast, school, or other activity.
During our teenage years our circadian rhythm is shifts forward. Some teenagers’ brains do not release melatonin until much later in the evening, way past sunset. So, while parents may be on their way to bed, their children may still be wide awake. The delay in the release of melatonin postpones the body’s response of getting ready for sleep and therefore makes it take longer for the teenager to get tired.
Sleep in Adulthood & Later in Life
By the time we’ve reached early adulthood, let’s say our early 20s, the proportion of REM sleep to NREM sleep we receive has usually stabilized at 20:80. These proportions don’t last long and we already experience a decrease in NREM sleep by our early 30s. By the time we’re in our 70s, we lose up to 90% of our NREM sleep. Sleep is also vital in processing and forming memories and a decrease in the amount of sleep may lead to a decline in memory-related functions.
As we get older, our biological clock turns back further, with earlier melatonin release causing us to fall asleep earlier in the evening and wake up earlier in the morning. On top of this, less melatonin is released overall, making sleepiness less readily available.
We understand that sleeping can be difficult and some nights we may need help falling asleep. Meditopia has a large library of sleep content from meditations to music and sleep stories that can help you fall asleep while improving your sleep quality. Everyone’s sleep habits are different, so it may be helpful to try a few different options to see which ones work best for you!
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