Why do we spend a third of our lives sleeping? 

That’s a considerable amount of time spent doing nothing apparently useful. You’d think, given our bodies’ amazing capacity to adapt, that Mother Nature would’ve allowed for us to find another way, a shortcut to not feeling tired. 

Afterall, it’s that inescapable need for slumber that seemingly keeps us from accomplishing so much more in our short human lives. What gives?

This article will cover how sleep operates within the body, ways to improve sleep, and several other topics touching on sleep hygiene, sleep quality. 

and individual considerations surrounding sleep.

What causes sleepiness?

A whole host of processes occur within the body to get us to the point of feeling ready for sleep. The two major reasons your body knows when to fall asleep are your circadian rhythm and your sleep/wake homeostasis. 

Circadian Clocks:

Every living organism from plants to insects to birds to human beings have a circadian clock.  It is what gives us our sense of time, our structured adherence to our ever-revolving planet around the sun. The very word “circadian” comes from Latin, meaning “approximately a day.” 

It controls many behaviors such as sleeping, eating, mating and migration.

Each cell in the body has its own circadian clock that gives temporal meaning to our bodies’ innate functions of survival.

With sleep, even when someone is kept in the dark, our bodies have an innate sense of time due to our internal circadian clock and we are able to sense when it is generally time to sleep and when it is time to be awake. 

Sleep/Wake Homeostasis:

The term homeostasis implies finding a balance. Body temperature, heart rate and hormone secretion are among several key factors that play into finding the right balance for sleep. When the body is ready for sleep, both heart rate and body temperature drop. Lack of light signals to the brain’s homeostasis control center that it is time for sleep and melatonin is secreted.

On the flip side, when our eyes are exposed to light, it signals to the brain that it is time for wakefulness. Serotonin and cortisol are released and our bodies are prepped for being awake and using energy to power through our day.

As the day progresses, we build up Adenosine, a by-product of ATP (think energy production), within the bloodstream and brain. This buildup signals to the brain that we have been using a lot of energy and that it is time to recharge and rest. While asleep, the adenosine is cleared out and rejoined to form ATP (Adenosine TriPhosphate) and the process starts all over again with wakefulness. 

The Four Stages of Sleep:

Now that you know what makes you want to sleep, let’s take a closer look at what happens when you pass into that state of unconsciousness.

Humans have a sleep cycle that lasts about 90 minutes. There are two main parts to your sleep cycle; Non Rapid Eye Movement sleep (Non-REM) and Rapid Eye Movement sleep (REM sleep). Note that each stage of sleep plays a vital role and that no sleep stage is more or less important than another. 

Non-REM 1: This is the closest state between sleep and wakefulness. This is where the body’s breathing rate and heart rate begin to slow down and body temperature falls. The brain’s electrical activity also slows down, preparing the brain and body for subsequent sleep stages. A phenomenon called hypnagogic hallucinations often occur in the stage of sleep where an individual may see flashes of light, hear voices or see paranormal visions. Non-REM 1 is also the point in the sleep cycle where an individual may have the feeling of falling that jerks them out of restfulness.

Non-REM 2: In this sleep stage an individual drifts into a deeper state of unconsciousness, making it increasingly harder to wake them. The brain begins sending out rhythmic bursts of activity and memories from the previous day are consolidated into long term memory storage. Within this sleep stage, the secretion of stress hormones used for wakeful activity is suppressed in the body’s attempt to remain fast asleep.

Non-REM 3: At this stage, an individual is considered to have entered “deep sleep” and will be very difficult to wake up. Brain wave activity is very slow. During this stage in the sleep cycle most sleep disorders occur such as sleepwalking and sleep talking. It is during Non-REM 3 that growth hormones are released and cell repair occurs. 

REM Sleep: Also known as paradoxical sleep because the brain’s activity is incredibly active as if someone were awake, but the body is literally paralyzed to prevent movement during dreams. Most dreams do, in fact, occur in this stage of sleep and we get a “boost” of creativity that allows us to piece together solutions for seemingly difficult problems. When someone tells you to “sleep on it” regarding a decision, this is exactly why; REM sleep is a powerful healing mechanism for our emotional health and gives us clarity into what may have been a troublesome dilemma the day before.

As previously mentioned, human sleep cycles last 90 minutes and undergo each of these four stages. As the period of sleep continues, REM sleep becomes longer in duration through the 90 minutes and deep sleep becomes shorter. Ideally, someone would wake up by the end of the sleep cycle after the REM stage. Not only does this allow for a smoother transition from sleep to wakefulness, it also allows someone to more vividly remember their dreams. 

Because the ratio of Non-REM sleep and REM sleep shifts in favor of REM sleep as the night progresses, waking up even an hour earlier than usual would mean someone is missing out on a higher percentage of REM sleep. As a result, they would also forego the benefits that come from enough REM sleep. This is a huge reason why it’s so important to get the full amount of recommended sleep. 

How much sleep should I get?

How much sleep you get can depend on a number of factors, including age, health problems, medications, and activity level.

Generally speaking, healthy adults require 7-9 hours of sleep each night. Adolescents and school aged children require a bit more sleep, around 9-11 hours each night. Small children and infants can require upwards of 16-18 hours of sleep each day! (Interestingly, a shift in circadian rhythm is regularly seen in teens, causing them to want to go to bed later and sleep in later into the day. So anytime you see a teen “wasting the day away” by sleeping in, realize that their sleep needs are just a bit different right now.)

Another tidbit about sleep requirements is that it may also change depending on illness or medication. If you find that your sleep needs have increased noticeably lately without a great explanation as to why then it may be time to see your doctor. Feeling like you need more sleep may be your body’s way of attempting to heal itself from another more serious underlying health condition.

Someone who is highly active will likely need more sleep compared to someone who is mostly sedentary because of the additional energy usage that occurs in the body during activity. The body will need more time to “recharge” itself after, say, the Boston Marathon than it will for a Netflix marathon.

We spend a considerable amount of our lives catching Z’s, but the fact prevails that sleep is the most valuable and efficient way for the body and mind to heal itself and reset for the following day…and subsequent days.

What happens when we don’t get enough sleep? 

Here’s the real core of the issue at hand; Whenever we lose out on sleep a lot of things happen that are not favorable to our health and goals.

It’s harder to lose weight

When we lack sleep, up to 70% of weight loss comes from muscle mass instead of fat mass. Yes, you read that right; 70%! That means that even if someone is eating well, is in a caloric deficit and is exercising regularly they will still have a much harder time reaching their fat loss goals simply due to a lack of sleep.

In addition, lack of sleep negatively affects the secretion and control of the two hunger hormones, ghrelin and leptin. 

Ghrelin is responsible for signaling to the brain that we are hungry and need to eat. When we are low on sleep, this hunger hormone is increased significantly, causing us to reach for more food to give us energy.

If that isn’t enough, leptin, the hormone that signals to the brain that we are full and no longer need to eat, decreases significantly. This means that we are less aware of our bodies’ actual hunger cues that we no longer have a need for energy. We are much more likely to continue eating beyond what our actual energy needs are.

Overall hunger has been shown to increase by up to 26% and sleep deprived individuals are much more likely to choose foods that are more calorie-dense and less nutrient-dense.

Risk of injury increases

Studies have shown a direct correlation between the number of injuries and how much or little an athlete slept during the season.

Beyond sports, being sleep deprived causes an individual to be more accident prone. The number of falls, failures to safely operate machinery and car accidents all increase in direct correlation to a lack of sleep.

Motivation and intensity in exercise decrease

If you’re someone who consistently works out while sleep deprived then you are not tapping into your full potential as an athlete. Other than just “feeling tired,” you may find that your overall performance suffers as well. Muscle contractions are much weaker when you are not well-rested, causing a decrease in overall strength. 

With less sleep you lack optimal coordination and decision making skills that are incredibly valuable in a lot of sports.

The exchange of carbon dioxide and oxygen within the respiratory system worsens, meaning that your overall cardiovascular fitness and health is performing suboptimally. 

Long story short, get enough sleep and you’ll do better in the gym.

Our thinking ability and emotional intelligence suffers

Studies have shown that employees significantly decrease in their work capacity and quality when they come into work sleep-deprived.

Oftentimes workload and deadlines are put ahead of sleeping enough, but if someone loses out on even the last hour or two of their sleep cycle, the bulk of the REM stage sleep is lost due to the increasing time spent in REM sleep as the night progresses. Recall that this is the stage of sleep where the brain is able to sort through problems and generate more creative solutions. According to sleep expert Matthew Walker, the REM stage is a form of “emotional first-aid” for an individual. Without enough time spent in this stage it becomes increasingly difficult for someone to operate at their full emotional capacity and then make thoughtful decisions accordingly.

We are more at-risk for disease

While at rest, our brain and bodies undergo a natural “reset” and are cleansed of built up toxins. Natural killer cells (K-cells) are regenerated and more equipped to fight off foreign substances that cause illness and disease.

When we are not well-rested our hormones become imbalanced, our stress levels rise and other disease causing components are raised. Our immune system takes a hit and we are more prone to illness such as the flu or common cold. At a more serious level, a higher risk of developing cancer and Alzheimer’s disease are all in direct correlation with being chronically underslept. 

The World Health Organization (WHO) has even deemed nightly shift work as a probable carcinogen because of its link to chronically underslept employees.

How Do I Get Better Sleep?

At this point in the article you may be thinking to yourself that you’ve lost out on hours of sleep and that your health will surely suffer now because of it. Well, not necessarily. There is still hope for even those people who regularly feel they have a difficult time sleeping!

Before diving into some basic sleep hygiene tactics for better rest, also consider that there may simply be other factors at play other than just too many environmental stimuli. Our modern society has become fast-paced and work-driven, leading to an undervaluing of sleep and an overvaluing of work. Even the very traditional structure of the workplace, school and other everyday activities revolves around certain set schedules that may just not be conducive to great sleep for some people. Here are some other factors to consider:

Know Your Chronotype:

Your chronotype is a genetic predisposition for when your circadian clock tells you it’s time for bed or time to wake up. You may consider yourself a “morning person” or a “night owl.” That’s essentially what chronotype is referring to. 

World renowned sleep expert and author, Matthew Walker, explains this further; Because we are at our most vulnerable when we are asleep, chronotypes are Mother Nature’s evolutionary solution for human beings to be able to get enough sleep without being exposed to danger for too long (think early humans). By each individual having a predisposition to going to bed at different times of night – some earlier and some later – this allowed for tribes to have someone with a watchful eye at most hours of the night. 

Fortunately and unfortunately, this same genetic marvel has prevailed through the years into our modern society. This can be a blessing for those early risers who favor the standard 9-5 work schedule. These individuals tend to thrive off this setup and are much more likely to sustain their work without burnout or other health issues arising due to lack of sleep.

However, only about 40% of the population are true morning birds. While our society tends to favor phrases such as, “The early bird gets the worm” it does not take into account that a large portion of people simply do not fall into that category. It is estimated that about 30% of the population are more in-sync with a later circadian clock. 

These are the folks who get their creative bursts at midnight and would happily stay up an additional several hours to get their best work in. These are the people who get a bad reputation for wanting to always sleep in. Truth is, these people aren’t being lazy, they’re just following their inner circadian clock and need to be on a different schedule than what our society tells them. People with a “night owl” chronotype are more likely to develop health problems, often due to sleep issues arising from simply not being able to rest when their body wants to. Even if they go to bed with enough time to get a full 8 hours of sleep, they may find themselves lying in bed, unable to fall asleep.

Another 30% of the population are estimated to be somewhere in the middle. They may be fine getting up in the morning, but not too early. They want to go to bed after the sun properly sets but not well into the wee hours of the night. These people often find their best creativity hits in the midday. 

It is important to recognize that each chronotype has great pros and cons, even in today’s society, but that it can be a bit trickier to manage when your bedtime should be, especially when you factor in work hours, family needs, travel and other personal needs. It is recommended that, if at all possible, you set a schedule that allows you to work with and not against your chronotype. This may mean rearranging work hours, if possible, so that you can go to bed and wake up at more favorable times for your body.

Also realize that if you are in a relationship, you and your partner may have different chronotypes. If you feel this is the case and that it could potentially be causing sleep disruptions then it may be beneficial to discuss possible solutions or sleeping arrangements.

Sleep Opportunity:

This refers to the amount of time you give yourself to get enough sleep. 

Say you’re aiming to get 8 hours of sleep. You climb into bed at 10pm and set your alarm for 6am. You’re getting a full 8 hours, right? Well, probably not. 

Realize it takes most people a bit of time to actually fall asleep. Factor in other sleep disruptions throughout the night and you’re sitting at less than 8 hours of sleep.

Sleep opportunity takes into account that there may be disruptions in your nightly rest and that you may need some time to fall asleep. If you want 8 hours, plan for 8.5 hours and see if you notice a difference in how rested you feel.

How does physical activity affect sleep and vice versa?

Getting enough physical activity can help with hormone production and other processes that allow our bodies to properly get tired and feel the need to sleep. Being physically active also allows for an overall healthier body, which allows our bodies to function properly, including in the sleep department.

While physical activity can help with better sleep, it is also important to time exercise properly around your bedtime. Try to finish vigorous physical activity more than a couple hours before your bedtime in order for your heart rate and body temperature to decrease appropriately and for your brain and body to be able to “wind down” properly.

How does caffeine and alcohol affect sleep? 

Caffeine is an adenosine-like substance. Recall that the build up of adenosine within the brain contributes to the feeling of sleepiness.  Biochemically, caffeine is very similar in its structure to adenosine and can bind to the same receptors in the brain; It binds to those receptors but does not activate them. As a result, the adenosine has nothing to bind to in the brain and it increasingly accumulates to the point where you may not be able to fully clear it out during sleep. This causes increased tiredness in the morning when you wake, often causing us to reach for even more caffeine, starting the process all over again and contributing to chronic fatigue. 

Alcohol, on the other hand, is sedative in nature. Because of this, it will indeed help you fall asleep more quickly. However, the sleep will be less than ideal with possible disruptions throughout your sleep cycles due to the liver enzymes metabolizing the alcohol. An individual will likely wake up feeling less rested. On top of this, an individual will often continue building up a tolerance to alcohol if they use it as a way to fall asleep. This means they will progressively need more alcohol to have the same effect. Alcohol, as we know, can have a host of issues accompanying excessive consumption of it.

Do Sleeping Pills or Other Supplements Help?

Sleeping pills are a form of sedative and do not actually promote a healthful sleep cycle. They can be used in some cases, but sleep expert Meeta Singh states that if you feel like you need to use sleeping pills then you should probably see a sleep doctor to understand if there is another underlying health condition. Common conditions that lead to poor sleep include sleep apnea, restless leg syndrome and mental health concerns such as depression or anxiety.

There are also many questions surrounding the usage of melatonin. While melatonin is generally considered safe to use, it’s also something that should be taken with some caution. Melatonin has indeed been shown to help those with sleep difficulties fall asleep better. It is also helpful for regulating your sleep schedule if you are traveling to another time zone and face jetlag. Melatonin is not, however, meant to be used long term for those who suffer from insomnia. At that point, it is important to stop taking it and see your doctor. According to an article put out by John Hopkins research, melatonin shouldn’t be used in large amounts and should be avoided by individuals who are pregnant, breastfeeding or who have autoimmune disorders, seizures or depression.

Tart cherry juice is another substance that has shown some mild positive effects on sleep. In a study put out by the Journal of Medicinal Food, study participants who took tart cherry juice before bed reported overall improved quality of sleep. This particular study group was small and more research is needed to gather conclusive data regarding the efficacy of tart cherry juice as a sleep aid.

Could it be Stress or Bad Associations with the Bedroom?

Sometimes a bad night’s rest comes down to the simple fact that someone is just too stressed out to turn their brain off properly for sleep to happen. If this seems to be the case then additional questions may need to be addressed around lifestyle, work, family life or other potential causes of stress.

Because of chronic sleep concerns, people may subconsciously associate the bedroom as a place to lie awake and stress about the reasons they can’t sleep, only perpetuating the issue at hand. Dr. Meeta Singh states that if you are having trouble sleeping then you should go to another room until you can fall asleep. If your brain associates your bed as somewhere you cannot sleep then it will only make the problem worse.

In either case, Behavioral Cognitive Therapy is a recommendation to help individuals rewire their brain and change their way of thinking around sleep and the bedroom.

Try Creating a Bedtime Routine:

Poor sleep may come down to you simply needing a better transition from wakeful activity to being asleep. Very few people are blessed with the ability to fall fast asleep once their head hits the pillow. If you are one of those people, read on and know that the rest of us envy you…

If you are a more typical sleeper then you’ll likely need some time to unwind and settle down before your body gets the hint that you want to sleep. Falling asleep is a process and has several things that need to happen (melatonin secretion, decrease in heart rate and body temperature…) before you arrive at the final destination.

Try to limit physical exercise to more than a couple hours before bed for your body’s internal temperature to drop enough and the heart rate to slow down. Dim the lights to signal to your brain that it’s nighttime and that you’re ready for sleep. Many people find that meditation or relaxation techniques can be helpful to prep them for sleep. 

What is My Checklist for Better Sleep?

We’ve covered some more prevalent issues in greater depth but oftentimes it’s great to just revisit the basics. 

✓ Do you have a comfortable mattress and pillow?

✓ Is the place you sleep dark enough and free of loud noises and distractions? Consider using a sleep mask, blackout curtains and/or ear plugs if needed.

✓ Is the temperature cool enough? Ideally it should be kept under 72 degrees Fahrenheit / 22 degrees Celsius.

✓ Do you have electronics in the bedroom? Consider moving them to another room to avoid distractions and too much light before bedtime.

✓ Avoid eating right before bedtime. Also avoid alcohol and caffeinated beverages late in the day to prevent sleep disruptions.

✓ Avoid strenuous physical activity too close to bedtime to allow your body to wind down and prepare for sleep.

✓ Create regularity around your bedtime. Try to be consistent both with your routine before bed and the time that you go to bed.

Conclusion:

By now you hopefully have a better understanding of how sleep works and why it is so vital to a healthy body and mind. Everything is improved in our lives when we prioritize getting proper rest. Not only do we just feel better, but we think better, are emotionally more resilient, and we will see better results in the gym.

Too often do we sacrifice sleep, hoping to get further ahead in our studies or career, often gaining a sort of rite of passage by pulling all-nighters. This culture of sleep deprivation needs to stop. It will only continue to cost us.

So let’s cycle back to our first question, “Why do we spend a third of our lives sleeping?”

The answer is quite simple. Sleep is what gives us life, quite literally. It will improve health and longevity and productivity. That’s what we’re all here for, right?