Sleep: Quantity, Quality, and Consistency

By Stefan Hanish

Sleep is important.

This statement is fairly common knowledge and probably won’t shock you. Anyone who has pulled an all-nighter or worked a night shift has already come to this revelation. Sleep is incredibly important for solidifying new information into long-term memory, maintaining a strong immune system, and allowing for the restorative functions of the body (not to mention that it makes you feel rejuvenated, happier, and more alert).

So, with the importance of sleep being known by all, the elephant in the room is: why are so many people not getting enough of it?

The CDC recommends that adults (over 18 years old) get at least 7 hours of sleep per night; however, a study they performed in 2014 shows that around 35% of all adults in the United States get less than that recommended amount [1]. This study went on to show that these same individuals, who were not getting sufficient amounts of sleep, were more likely to be obese, physically inactive, and smokers while also having significantly higher rates for heart attacks, heart disease, strokes, arthritis, depression, and even cancer than their counterparts, who reported having sufficient sleep time [1].

After reading this article, you should have a better idea about how much sleep you need, how to get the most out of your sleep, and several beneficial sleep hygiene tips.

Quantity

The recommended amount of sleep for an adult is 7-8 hours per night. For teens and younger children, this amount is slightly higher as the chart to the right shows [16].

Getting these seven precious hours of sleep allows your body to consolidate memories of events that took place during the day into long-term storage and perform “major restorative functions in the body like muscle growth, tissue repair, protein synthesis, and growth hormone release,” which all primarily occur during sleep. [2]

Now, I understand these are vague terms and droning on about tissue repair and protein synthesis doesn’t promote the greatest understanding of the actual effects of not getting enough sleep.

So, what are some of the more tangible consequences of getting less than seven hours of sleep on a regular basis? Not only are you going to be tired and sleepy throughout the day, but also you are increasing your risk for weight gain, high blood pressure, diabetes, heart attack, stroke, and impaired immune function [3].

Not getting an adequate amount of sleep also wreaks havoc on your body’s hormone production. Two hormones in specific that are affected by lack of sleep are ghrelin and leptin. These two hormones have opposite effects on the body. Ghrelin is a hormone that increases your appetite; while, leptin is a satiety signal that decreases your appetite. However, a study performed in 2012 has shown that people who do not get enough sleep have increased production of ghrelin and decreased production of leptin [17]. This imbalance means that those individuals have greater feelings of hunger throughout the day. And, we all know what happens when we feel hungry. We eat to satiate that hunger. Thus, feeling more hunger throughout the day will increase the probability of overeating leading to weight gain. For people trying to lose weight and stay healthy, this can slow their progress or bring it to a screeching halt.

In addition to these physical effects, lack of sleep also affects your cognitive performance. Studies show that the work you do perform during the day will be affected by impaired performance, increased errors, and increased accidents [3]. To give you a more concrete idea of what this cognitive impairment is like, the impairment of performance caused by 20-25 hours of sleeplessness is comparable to the impairment caused by a blood-alcohol level of 0.10% (which is 0.02% over the legal limit) [4]. In the eyes of the law, you aren’t even allowed to drive with this kind of impairment, but many people try to perform their jobs on a daily basis like this.

The main things that are causing this cognitive impairment: microsleeps. These very short moments of inattentiveness, which we have all experienced when we’re tired, have actually been shown to produce sleep like brain activity [5].

This impaired cognitive performance from lack of sleep causes you to not only make more errors in the work that you do but also causes it to take longer to accomplish tasks. Think about it, who is going to finish a task at work or complete all their errands first? The person who got 8 hours of sleep last night? Or the person who got 4 hours of sleep? The less sleep you get, the longer it will take you to grind through your daily to-do list. And the longer it takes you to complete the individual tasks that make up your day, the less free time you’ll have at day’s end for activities like exercise, time with your family, or cooking a healthy dinner. Getting adequate sleep, so you are mentally focused to power through your day can result in you having more time to spend on the things that personally matter to you (family, fitness, hobbies, etc…) but sometimes get thrown by the wayside.

Finally, probably the most obvious consequence of not getting enough sleep is just feeling tired and sleepy throughout the day. I think I can speak for most, if not all, people when I say that the last thing that I want to do when I’m incredibly tired is put on my workout clothes and drive to the gym. So, on the days where I don’t get enough sleep, I’m also not active. If not getting enough sleep becomes a trend in your life, you can severely hinder your motivation for daily exercise, resulting in a more sedentary lifestyle. This can spell trouble for those who have set fitness goals in their life.

Now, I wish I could offer some easy “life hack” that will magically allow everyone to get 7-8 hours of sleep per night, but the harsh reality is that such a hack doesn’t exist. However, hopefully, what I have said so far has helped you more clearly see the importance of getting enough sleep, and, later on in this article, I can and will offer some ways to structure your day that might just be able to help you sleep better more consistently (WARNING: this will include some hard work and commitment). But, there is a silver lining. How much sleep you get is only one component of how good your overall sleep is. Quality of sleep also plays a crucial factor. And for this, there are some easy ways to improve it.

Quality

Have you ever laid in bed unable to fall asleep? Woken up frequently in the night? Or even worse, woken up to the sound of your alarm but still felt exhausted? I’m sure these scenarios ring true for some of you. The issue here isn’t “not enough sleep,” but, instead, lack of quality sleep. Sadly, getting under the covers and closing your eyes at 10 PM doesn’t always guarantee that your sleep will be perfect. To address these issues, we turn to sleep hygiene.

Sleep hygiene is defined as “behaviors that are believed to promote improved quantity and quality of sleep” [6] and includes things ranging from the obvious “no caffeine before bed” to the more obscure “keeping your bedroom’s temperature low.” Let’s explore!

No caffeine before bed

Why do we drink coffee? Because the caffeine in it wakes us up and makes us more alert. Caffeine is a stimulant that has its effect by “blocking sleep-inducing chemicals in the brain” [7]. Therefore, it’s not a good idea to drink coffee anywhere near bedtime. As the half-life (time it takes for your body to eliminate half of it) is 3-5 hours, “one study found that consuming caffeine 6 hours before bedtime reduced total sleep by 1 hour” [8]. So, avoid coffee after about 4 PM.

Blue light

These days, nearly everyone owns a smartphone or works on a computer or watches television. What do these devices have in common? Screens. And what do these screens produce? Blue light.

Recent studies have shown that exposure to blue light affects our body’s production of melatonin. Melatonin is a hormone we naturally produce that regulates our “night and day cycles or sleep-wake cycles” [9]. Essentially, as the sun goes down and it becomes darker outside, our body produces more of this hormone to make us sleepy; thus, making it easier to fall asleep. However, the blue light (from, say, our smartphones), decreases the body’s production of melatonin, reducing our body’s ability to prepare for us for sleep. Studies have shown that with less melatonin being produced, the time it takes for people to fall asleep increases [10] and it is also harder to stay asleep throughout the night [11]. These consequences result in those same people being less alert in the morning [10].

So what’s the takeaway? Give yourself a breather from using technology before bed. It doesn’t have to be long but taking at least 30 minutes, can help you fall asleep and stay asleep throughout the night [11].

Light intensity

On the same note as the last point, being exposed to bright light near bedtime can also throw off our night and day cycles. Think about it. What’s the biggest clue our body has that it’s time to go to bed? The sun going down, and it becoming darker outside. Exposing yourself to bright, artificial light at night doesn’t allow your body to understand that it’s time to start gearing down. It does so by way of the same melatonin pathway as stated before. So, just as with blue light, try to keep the brightness of the lights in your home lower near bedtime. This effectively tells your body that bedtime is approaching.

Room temperature

This tip uses the same method of thinking as the previous two. As bedtime draws near, we should be doing things to help our bodies become sleepy naturally. Sleeping in a cool room is another way of doing just that.

Our body temperature actually lowers to help initiate sleep [12]. So, keeping your bedroom’s temperature cool helps to stimulate sleep and also “allows you to cycle naturally through sleep stages” [13]. Sleep.org proposes that bedroom temperatures in the range of 60-67 degrees Fahrenheit are best [12].

Using bed for sleep and sex

Okay, this might be the biggest one yet. Many of us like to use our beds to finish up some extra work, surf the internet, watch a movie, or even for some late-night snacking. However, using your bed for these “waking-hour activities over an extended period of time” can cause your brain to link your bedroom to activating stimuli (activities you do when you’re fully awake) [14]. This can cause getting into bed to be “associated with alertness and activation” rather than “triggering sleep” [14]. By refraining from these activities while lying in bed, we can retrain our brain to associate our bed with bedtime and sleep rather than making it yet another place to work, eat, and soak up new information. So in the interest of getting better sleep, it is best to use your bed solely for the two activities for which it is meant to be used: sleep and sex.

Consistency

Now that you have an idea of how much sleep you should be getting and what to do and what not to do to achieve the highest quality of sleep, it’s time to put it all together to create a consistent and structured routine. Being consistent with your sleep is the only way to make a real change. When talking about sleep, consistency refers to when you go to bed, when you wake up, how much sleep you get each night, and what you do before bed.

Going to bed and waking up at around the same time each day is extremely important. Now, I’m not saying that sleeping in on a lazy Sunday or staying up late to watch a movie is a bad thing. Just make sure you’re not regularly pushing your bedtime or morning alarm by more than 1-2 hours. Studies have shown that having a highly “irregular bedtime schedule affects sleep quality by disturbing the circadian rhythm,” that all-important internal clock that we have that helps us figure out when to sleep and when to be awake [15]. By consistently going to sleep and waking up around the same time each day, your brain will begin to learn when the correct time to be awake and when the correct time to be sleepy is. This will help decrease that daytime sleepiness that causes you to make simple mistakes at work and be unproductive during the day.

Tips to becoming more consistent with your sleep include:

  • Developing a morning and nighttime routine, which can help gear your body up for the day or wind down at night, respectively
  • Keeping a sleep journal to provide yourself feedback (tip: “Sleep Cycle” is a free app that you can use to track your sleep)
  • Setting a “cut-off time” at night, at which you stop working and start winding down your day
  • Making a to-do list at night for the next day to give yourself tangible motivation to get out of bed in the morning, so you don’t wind up staying in bed with the risk of falling back asleep

Conclusion

Sleep is a very important part of our day. When you get enough of it, you feel prepared and energized to take on everything the rest of the day can throw at you. But if you don’t get enough, you can float through the day in a haze and, even worse, put yourself at higher risk for several dangerous chronic diseases.

So, in summary:

  • Get 7-8 hours of sleep per night
  • Avoid certain activities at night that could throw off your sleep (drinking caffeine, bright lights, using your smartphone or laptop, etc…)
  • Be consistent about when you go to bed and when you wake up

These are some evidence-supported, general tips that can help you get better sleep. Some can be easy to adopt, while others can be much harder. That’s okay! Everyone is different, and everyone needs different things. However, adopting just one or two of these habits can have an amazing effect on your sleep. Start with small steps and gradually incorporate more. As the saying goes, “a journey of a thousand miles begins with a single step.”

 

 

 

References:
[1] Sleep and Sleep Disorders – Data and Statistics (https://www.cdc.gov/sleep/data_statistics.html)

[2] Why Do We Sleep, Anyway? (http://healthysleep.med.harvard.edu/healthy/matters/benefits-of-sleep/why-do-we-sleep)

[3] Recommended Amount of Sleep for a Healthy Adult: A Joint Consensus Statement of the American Academy of Sleep Medicine and Sleep Research Society (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4434546/)

[4] Consequences of sleep deprivation. (https://www.ncbi.nlm.nih.gov/pubmed/20442067)

[5] Sleep deprivation: Impact on cognitive performance (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2656292/pdf/NDT-3-553.pdf)

[6] Association Between Sleep Hygiene and Sleep Quality in Medical Students (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3572193/)

[7] CAFFEINE AND SLEEP (https://www.sleepfoundation.org/sleep-topics/caffeine-and-sleep)

[8] Sleep and Caffeine (http://www.sleepeducation.org/news/2013/08/01/sleep-and-caffeine)

[9] MELATONIN (https://www.webmd.com/vitamins/ai/ingredientmono-940/melatonin)

[10] Timing of light exposure affects mood and brain circuits (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5299389/)

[11] Scary Ways Technology Affects Your Sleep (https://www.sleep.org/articles/ways-technology-affects-sleep/)

[12] The Ideal Temperature for Sleep (https://www.sleep.org/articles/temperature-for-sleep/)

[13] Sleeping in a Cold Room is Better for Your Health (https://www.thesleepjudge.com/sleeping-cold-room-better-health/)

[14] Use your bedroom for sleep and sex only (http://sciencenordic.com/use-your-bedroom-sleep-and-sex-only)

[15] Effects of an irregular bedtime schedule on sleep quality, daytime sleepiness, and fatigue among university students in Taiwan (https://www.ncbi.nlm.nih.gov/pmc/articles/PMC2718885/)

[16] https://www.sleepfoundation.org/excessivesleepiness/content/how-much-sleep-do-we-really-need-0

[17] https://onlinelibrary.wiley.com/doi/full/10.1002/ajhb.22219