Sleep is essential for physical performance, cognitive functioning, and mental health. A proper night’s rest makes us feel rejuvenated, energized, and motivated to start the day. Lack of sleep, on the other hand, can wreak havoc on our bodies, minds, and overall outlook on life. Unfortunately, most of us don’t get enough sleep on a regular basis. The National Sleep Foundation notes that adults between the ages of 18 and 64 require seven to nine hours of sleep per night — but a recent poll by the Centers for Disease Control (CDC) suggests that more than one-third of adults in the U.S. get fewer than seven hours of sleep per night.
There are a myriad of reasons why adults don’t get enough shuteye. Some are natural night owls prone to staying up late, even on weeknights. Others consume too much sugar, or drink caffeine and/or alcohol before bedtime. Sleep disorders may play a role, as well; millions of Americans struggle with insomnia alone, and other conditions like sleep apnea, restless legs syndrome, and parasomnia can also significantly disrupt sleep. Many people turn to prescription medications or cognitive behavioral therapy to alleviate their sleeplessness. These methods have proven results — but studies have also shown that people can improve poor sleep on their own by adjusting their daily routines and maintaining a healthy sleep schedule.
We’ll discuss what it means to have proper ‘sleep hygiene’ and share a few science-driven hacks that will help you sleep better and wake up feeling rested. First, let’s discuss how sleep works from a scientific perspective — and why it’s crucial to get enough sleep each night.
How We Sleep
Sleep in humans is directly tied to our circadian clock, an internal timekeeper that is designed to follow a 24-hour cycle known as circadian rhythm. Circadian rhythm is regulated in the suprachiasmatic nucleus (SCN) region of the hypothalamus gland found in our brains. The SCN uses receptors to track natural daylight and temperature, and produces a sleep-inducing hormone called melatonin when the receptors indicate nighttime has arrived.
As a result, we feel alert and refreshed during the daytime — when it is lighter and relatively warmer — and start to feel sleepy after dusk when it is cooler and darker. Humans naturally feel the sleepiest between 12am and 6am. The immune system also plays a role by releasing sleep-inducing chemicals called cytokines. This is why you tend to feel fatigued when you are sick.
In healthy adults with a functioning circadian rhythm, sleep is broken up into two phases: non-rapid eye movement (NREM) and rapid eye movement (REM).
- The first NREM stage consists of two light sleep stages that kick in right when you doze off. Your muscles relax, your brain activity slows down, and you heart rate slowly drops — but because it is light sleep, you will be easily awakened by noises, movement, and other disruptions.
- The second NREM stage consists of two deep sleep stages, also known as slow-wave sleep. Your body will stop moving as your blood pressure and heart rate hit their lowest levels.
- Together, the two NREM stages last roughly 30 minutes. After half an hour, the REM phase will begin. This phase is characterized by deep sleep and dreaming, as well as shallow breathing and increases to your heart rate and blood pressure. Your eyes will also dart back and forth below your closed eyelids, hence the name.
The average adult will cycle through the NREM and REM phases every 90 to 120 minutes, meaning they experience four to six cycles during eight hours of sleep. Unfortunately, the circadian rhythm is fragile and easily disrupted by bad habits, unhealthy food, physical discomfort, and other mitigating factors. And because the circadian rhythm is tied to your overall health, not getting enough sleep can cause negative side effects, including:
- Muscle fatigue
- Poor concentration and memory recall
- Mood swings
- Low energy and motivation
Additionally, lack of sleep can put you at greater risk of being involved in a car crash or a workplace accident. It can also affect your employment status. According to a study by the Journal of Clinical Sleep Medicine, roughly $40 billion in revenue is lost in the U.S. every year due to drowsiness-related accidents and poor work performance.
What Is Sleep Hygiene?
Originally, ‘sleep hygiene’ referred to the literal cleanliness of one’s sleep environment in regard to bed bugs, dirt, and other contaminants. Today the term applies to practices and habits — both good and bad — that impact your ability (or inability) to get a good night’s sleep on a regular basis.
Here are some factors that affect sleep hygiene:
- Mattresses and bedding materials
- Sleepwear choices
- Room temperature
- Light and noise levels
- Pre-bedtime activities
- Prescription medications (and their side effects)
For those who have difficulty falling and/or staying asleep, improvements to sleep hygiene practices and habits can make a significant difference. On the other hand, poor sleep hygiene choices can transform a healthy adult into a sleep-deprived zombie.
Some bad sleep practices may be unavoidable. For instance, recent studies have noted widespread sleep problems among people who work night/graveyard shifts. A primary reason why shift workers struggle to sleep is because lack of sunlight and exposure to darkness can meddle with circadian rhythm. As a result, many shift workers return home after a full night’s work feeling restless and alert when they are getting ready for bed. These employees also tend to experience drowsiness and lack of concentration while they are at work. In the auto manufacturing industry alone, the incidence rate for workplace accidents increases by 30% to 50% during night shifts. Poor sleep conditions among these employees are so common that they have received a medical classification: shift-work sleep disorder. Shift workers are also prone to heart problems, digestive issues, and infertility, and drowsy driving — another commonly reported trend among shift employees — is a major public health problem, as well.
Historically, sleep scientists and researchers have experimented with ‘workaround’ strategies to a good night’s sleep. The U.S. military has led the charge on many of these studies. In the 1940s, stimulants like modafinil — as well as amphetamines — were distributed to pilots and other personnel who worked at night. More recently Special Forces units have provided sleep-inducing z-drugs to soldiers to ensure they are well-rested before missions. Pilots today are given helmets fitted with lights to mimic sunlight and keep them awake. The U.S. Defense Advanced Projects Research Agency has also developed the Somneo mask, a heated device that fits snugly over the face to block out light and regulate body temperature.
Sleep restriction is another experimental strategy that has gained traction in recent years — and also generated a fair amount of controversy. Studies have shown that some humans are able to voluntarily reduce their sleep time from eight hours to as few as six per night without altering circadian rhythm. However, sleep restriction has yielded mixed results, and supervision is crucial to ensure subjects don’t experience any adverse effects. Another technique known as transcranial direct-current stimulation (tDCS) is designed to stimulate the temples with a slight electric charge. The FDA has approved tDCS for treatment of some brain disorders, and researchers hope it will someday be used to induce slow-wave sleep in people with insomnia and other sleep issues. Similar tests have been run using a technique known as transcranial magnetic stimulation, which has been approved to treat depression; scientists believe this form of stimulation can enhance sleep quality while also shortening sleep times.
However, none of these experimental methods should be considered a ‘cure’ for a healthy night’s sleep. While they may relieve symptoms of tiredness and fatigue, they cannot replace the importance of healthy, restful sleep. In lieu of a scientific miracle that allows us to sleep less without experiencing any negative effects, improving sleep hygiene habits and practices is the best course of action for most of us.
Tips for Better Sleep Hygiene
Below you will find a list of expert strategies for falling asleep, staying asleep throughout the night, and waking up refreshed each morning.