People have been trying to understand sleep from the dawn of time. Until scientists delved deeper into the process of sleep and finally understood why it takes place, it was quite difficult to comprehend. How could our body simply shut down, forcing us to enter a temporary state of unconsciousness before waking up feeling refreshed? Does our brain temporarily shut down too? And what’s the deal about dreams? These are only some of the things we didn’t understand all those years ago. Let’s dig into some of the most interesting facts about sleep, some of which you may find surprising.

The reason why we sleep

Even today, sleep largely remains a mystery. We know that we need to sleep at night to replenish our energy and function normally throughout the day. The problem with analysing sleep is that most methods of measuring are obtrusive therefore impact any true data we might be able to gather. We know that the body needs rest after being up all day so that it stays healthy and strong. It needs to recover. But why do we really need to sleep? We know why we need to eat, but we still don’t fully understand the whole concept of sleep. One piece of research on sleep function suggests that sleep is the key to boosting neuroplasticity or brain plasticity. That’s the brain’s ability to “rewire” itself and help us improve memory, filing everything we’ve learned during the day into our long-term memory. It also suggests the brain replenishes energy. Another study on sleep suggests that sleep helps the brain get rid of toxins in the central nervous system, while yet another study says it helps regulate metabolism. Perhaps all the evidence is true, and perhaps our brain is even busier protecting our overall health. We simply don’t know for sure – yet. What we do know is if we get enough shut-eye every day, we’ll reduce mental and physical fatigue, and stay healthy.

Sleeping cycles

There are five sleeping cycles, which can be divided into two primary phases of sleep:

• Non-REM (NREM) sleep
• REM (Rapid Eye Movement) sleep

Non-REM sleep consists of four sleeping cycles:

1. Drowsiness and falling asleep
2. Light sleep
3. Moderate to deep sleep
4. Deep sleep

The fifth sleeping cycle (REM sleep) is when your brain is most active, and usually when you start dreaming. It lasts about 90 minutes. It is believed that the fourth non-REM and REM cycles are when your brain performs most of its restorative functions. Depending on how long you sleep every night, you may go through all these cycles 5-6 times per night, except you spend more time in REM sleep with each new cycle.

Optimal sleeping time

As we age, we need fewer hours of quality sleep to stay fully functional and healthy. According to Sleep Foundation, babies need 14-17 hours, teenagers need 8-10 hours, adults need 7-9 hours, while older adults (65+) need 7-8 hours of sleep every day. The truth is there’s no magic number for everyone in the same age group. Your work hours and daily habits may affect how much you sleep.  

The chemistry behind sleep

Your body constantly releases various hormones and chemicals during the 24-hour cycle of your circadian rhythm (internal clock), which responds to light and darkness. At night, your body increases the production of melatonin, a hormone that regulates the sleep-wake cycle. So, when your homeostatic sleep drive (let’s call it your internal timer) reminds your body to sleep at night, melatonin is what helps you fall asleep faster and get a good night’s rest. That’s why screens emitting blue light can interfere with your sleep. They trick your body into thinking that it’s still daylight, so it produces less melatonin, preventing you from falling asleep faster. Jet lag and working night shifts can offset your internal clock the same way.

Lack of sleep and our body

According to a study on sleep disruption, chronic lack of sleep can be detrimental to your health. Sleep deprivation can:

• Increase stress, pain, anxiety, and depression
• Cause deficits in memory, cognition, and performance
• Reduce alertness and concentration
• Increase appetite and cause weight gain
• Increase the risk of heart disease and high blood pressure
• Worsen gastrointestinal disorders
• Increase the risk of infection and various illnesses
• Worsen underlying medical conditions

So, sleep is clearly one of the most important processes for overall health, and we shouldn’t sacrifice it for anything.

Genetics and sleeping

Your genes may be responsible for how long you sleep every day. For instance, one extensive research of genome-wide association studies confirmed that insomnia is hereditary. The researchers have also found the genetic link between insomnia and depression, among other psychiatric disorders, as well as type 2 diabetes. Other scientists have also found genes associated with sleep disorders like narcolepsy, sleep phase disorder, and restless legs syndrome. So, whether you’re a night owl or a morning lark, you can probably thank your genes for sleeping too little or too much.

Environmental issues and sleeping

A growing body of research on environmental sleep factors shows that the conditions we sleep in significantly affect our quality of sleep. You already know about the light (especially blue light from electronics), but environmental noise and temperature can also greatly impact sleep. Traffic, revving cars, honking, loud music, and loud neighbours can all hinder your sleep. So, make sure you eliminate all environmental issues before hitting the hay each night.

Dreams

As mentioned, you usually dream in the REM phase of sleep (more vivid dreams) but can dream in all sleep cycles. We still don’t understand how or why we dream, but we know dreaming plays a part in emotional processing. It can help us overcome waking-life emotional difficulties by experiencing them while dreaming. That’s how we can overcome fears, for instance, because we feel as if we’ve lived through them already.

Conclusion

To say that sleep is paramount for good health would be an understatement of the century. Although we still have a lot to learn about it, we know we can’t live a normal, happy, and healthy life without proper sleep. So, for your impeccable health and well-being, develop high-quality sleep hygiene.