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The Science of Sleep

To begin, check out this TED talk: A Walk Through of Sleep for a brief introduction into what sleep is as well as how it can be understood from a scientific perspective.

What Are Sleep Cycles?

As the video above mentioned, your sleep is divided into stages. To start, non rapid eye movement sleep, often shortened to the abbreviation NREM, is comprised of 3 stages. Both stage 1 and 2 are referred to as light sleep, with stage 3 being deep sleep. In stages 1 and 2 the body’s heart rate and temperature decreases and your brain waves slow down. In stage 3 brain waves get bigger as the brain is recharging itself while taking care of your cardiovascular system and consolidating memories. The higher stage of NREM sleep a person is in, the harder it is to wake them.

There is also rapid eye movement, or REM sleep where dreaming and other important functions occur.

Sleep cycles are about 90 minutes, so the body goes through NREM and REM sleep in that 90 minutes and then it resets. It’s recommended that we get at least 4-6 cycles, so 6-9 hours of sleep per night. 

As the video mentioned, in the first half of the night, (the 1st to 3rd sleep cycle) the body spends more time in the NREM stage of deep sleep. The second half of the night, there is more REM and light sleep.

Looking at the stages of sleep deeper,

1. Stage 1 is essentially the stage you enter when you first fall asleep. Brain activity starts to slow down and it’s easy to wake someone up during this sleep stage. This stage is usually only 1-7 minutes long. If you sleep uninterrupted through the night you may not spend much more time in this stage when your cycle repeats.
2. Stage 2 our brain waves slow and eye movement stops completely. We typically spend about half of our sleep in this stage when all is said and done.
3. Stage 3 we enter deep sleep. It’s harder to wake someone up here and if we do wake up in this stage, we’re much less likely to feel rested throughout the day. We may wake up feeling more groggy. In this stage our body relaxes even further. Experts believe this stage is critical to restorative sleep, allowing for bodily recovery and growth. It may be this stage that really works to help our immune system and other body systems. 

During REM on the other hand, our brain activity really picks up, nearing levels seen when we’re awake. Even though the eyes are closed they can actually be seen moving really quickly, hence the name of rapid eye movement. REM sleep is believed to be vital for cognitive functions like memory, learning, and creativity. Remember, as the night goes on our REM stages get longer, so this is part of why it’s recommended that we sleep for at least 7 hours. Dreaming can occur in any stage but they are more common and intense in REM. 

Check out the Sleep calculator from the Sleep Foundation which provides recommended sleep and wake times based on your age and in conjunction with sleep cycles and the time it takes for the average person to fall asleep.

What is Circadian Rhythm?

Put simply, our circadian rhythm is the body’s 24 hour internal clock.

Our internal clock is naturally aligned with the cycle of day and night and is influenced by light and dark. Travel, work, or underlying issues can disrupt our circadian rhythm. 

Our circadian rhythm affects many bodily processes, as well as our mental state, and even our behaviour. 

Our circadian rhythm helps regulate our sleeping and waking, hence why when jet leg hits so hard – our circadian rhythm is disrupted. It also regulates our core body temperature and our immune system. It helps keep our hormones in homeostasis and in balance, as well as our metabolism. 

When we look at sleep, keeping a consistent routine and sleep schedule helps maintain a healthy circadian rhythm and in doing this, we’re more likely to experience better sleep quality since our circadian rhythm is supported and is then able to regulate our sleep.

Melatonin is a hormone our brain produces that induces sleepiness and works with our circadian rhythm to regulate our sleep-wake cycle in telling our body its time to wind down and prepare to sleep

When our brains see light, it believes that it should inhibit melatonin release because it doesn’t want us to fall asleep during the day. As we’ll see, this is one reason that bright screens like a tv or phone can hurt our sleep hygiene and make it harder to fall asleep. 

Is Technology Really That Bad?

Studies have shown that technology can affect circadian rhythms and melatonin release, impacting sleep negatively. As mentioned, this is especially true for technology that has bright screens since melatonin release is influenced by light exposure 

Delayed sleep is also common in people who use technology before bed as the bright lights can stimulate our eyes. Additionally, many apps that we’re using, the video games we may be playing, or the tv shows or videos we’re watching are also going to mentally stimulate us and may make it harder to fall and stay asleep since these things are designed to be entertaining and keep our brain engaged. In this way we’re not giving our brains the time to relax before we sleep. Technology usage is also potentially going to cut into our sleep time too, same as anything we do before bed

Studies have also shown that technology use before bed can also reduce how long we’re able to stay asleep for and reduce our sleep quality too

With melatonin suppression from bluelight we may sleep less as well. A study comparing sleep patterns in those who read before bed time using a paperback book vs. a e-reader that emitted blue light found that those who were receiving blue light exposure took longer to fall asleep, rated poorer sleep quality, and reported feeling less alert the next day

Recommendations

Here are a few recommendations when it comes to technology and sleep

For starters, many sources recommend using a blue light filter if possible, as well as turning our devices to dark mode or at least turning brightness down as well. Findings suggest that a blue light filter isn’t enough to make a substantial difference if our brightness is still all the way up. The photo on the right shows a device with it’s dark mode on. Dark mode and turning the brightness down on our devices is going to lessen the strain on our eyes and lessen the light we’re receiving. Some sources do recommend you have a blue light filter or dark mode on all the time for your eye health so we should do our best to at least put a filter on in the evenings. For many devices you can turn on timers so that these go on automatically

It’s also recommended that we try our best to limit our electronic use at least 30-60 minutes before bed. Again, this is going to help us relax and give our eyes time to rest

In terms of other senses, it’s also recommended that we turn our volume down too. Just like with our eyes, if our ears aren’t having to work as hard before bed our minds are less likely to be awake. This doesn’t necessarily mean we need silence, but if we are watching tv, or listening to music, or anything else in the evenings it can be helpful to consume media at quieter levels

Finally, if we wake up during the night it can be really helpful to not check our devices if we wake up during the night. Once our eyes are hit with direct light and our minds stimulated, it’s going to make it that much harder to fall back asleep

Strategies for Limiting Technology Use Before Bed

Now easier said than done, let’s take a look at some of the strategies we can employ to try and limit our technology use before bed.

First, it can be really helpful to silence our notifications at night or turn on do not disturb mode. Like blue light filters and night mode, we can often go into the settings of our devices so that our notifications are automatically silenced at a certain time. If we’re never wanting to have our notifications silenced for specific people such as close family or friends in case of emergency, there are ways to silence notifications from others, while keeping notifications from those we do want to still receive them from

In addition to this, it can be really helpful to either charge our devices in a drawer, or somewhere away from our bed. This way we’re not tempted to go on our phones if we have a hard time falling asleep or if we wake up in the night

We can also set timers on our apps in the settings of many devices, for example, on iphones you can set limits on apps so that once you use them for a certain amount of time you get kicked out. Or, you can make apps “go to sleep” at certain times as well. If your device doesn’t have this option there are often apps that you can download that will do this for you

Finally, we can try and replace our device usage before bed by trading it for something else

Apps to Help Aid Sleep

• Noisli and apps like it provide a variety of background sounds that you can mix and match to create a relaxing atmosphere to sleep
• Calm and similar apps offer guided meditations, sleep stories, and relaxation techniques you can use to usher in a more restful sleep
• Sleep Cycle and apps like it track your sleep patterns and wakes you up during your lightest sleep phase, helping you feel more rested. Many devices like Fitbits and smart watches can also monitor our sleep and help us track our sleep cycles

Resources and Sources

Websites:

• Sleep Foundation
• Sleep Education
• CDC on Sleep and Sleep Disorders
• World Sleep Society