How Sleep Works
Updated: Mar 31
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Sleep is a subject about which I am very passionate. Having struggled on and off with various sleep issues at different times, I know how precious a good night’s sleep can be and how impaired one can feel when that is compromised. After having studied sleep closely over many years, I have been shocked at just how much confusion there is out there about this topic. Along with diet and exercise, sleep is one of the very cornerstones of good health. There is no good health without it. This post will provide some solid essential information to help you get the most out of your own sleep!
Benefits of Good Sleep
Who doesn’t appreciate how much better we feel and function after a good night’s sleep?! Physically, we have more energy and are much more regulated physiologically if we are sleeping well. Restorative sleep promotes good blood sugar balance, immune system function, cardiovascular health, hormonal health, weight control, detoxification, and athletic performance.
Did you know that inadequate sleep can affect the development of diabetes? One study took 19 healthy young men and restricted them to 4.5 hours of sleep per night for 4 consecutive nights. Interestingly, this was sufficient to induce a prediabetic state!
Mental health benefits of sleep include better mood, memory, focus, attention to detail, productivity, reasoning, judgment, and intellectual function. Being awake for 17 hours or 24 hours is equivalent to having a blood alcohol concentration (BAC) of 0.05% or 0.10%, respectively. (In the U.S., the threshold for drunk driving is .08%.). Although there are numerous alarming statistics related to sleep loss, we do not need to look at these to know that we are compromised on multiple levels when sleep deprived.
Sleep Quantity & Quality
There are many people who will insist that they function just fine with 5 hours of sleep a night as they have trained themselves to do this. Just because this phenomenon is common does not make it normal or okay. Most of us need 7 to 9 hours a night in adulthood. Needing less than 6 hours of sleep is an anomaly referred to as “short sleep” and applies to only a small percentage of the population. Babies, children, and adolescents generally need more sleep than adults do. People ages 65 and up may need less sleep, but this also depends upon activity levels. In retirement, life can be also less demanding, which may explain needing slightly less shut eye.
It may seem that sleep and wakefulness are 2 separate states, but all sleep is not the same, just as all waking states are not. Indeed, dreaming while asleep is comparable to being in a wakeful but very relaxed state of creative “flow” in terms of brain wave activity.
A healthy night of sleep can be better understood looking at a hypnogram, which is a picture showing a typical progression through various sleep stages throughout the night. This hypnogram shows an ideal night of sleep for a 7 to 7.5-hour sleeper.
There are 3-4 non-REM stages of sleep, depending upon your source, and REM sleep (dreaming). Stages 1 and 2 are considered light sleep, while stages 3 and 4 represent deep sleep. We sleep in cycles lasting 1.5 to 2 hours apiece. When we first fall asleep at night, we progress pretty quickly down to deep sleep for a while, then return up through the lighter sleep stages to a very short dream. We then plunge down to deep sleep once again in the next cycle, but for slightly less time in deep sleep before progressing upward to a slightly longer dream. Sometimes, in the peaks of REM sleep between deep stages, we can also experience a momentary “micro awakening” of which we may not even be aware.
This pattern continues throughout the night to yield 5 to 6 sleep cycles, depending on our sleep needs. The first half of the night, with its preponderance of deep sleep, is thought to provide us with more physical restoration. The second half, time in which progressively longer periods of dreaming occur, is thought to focus on the mental and emotional realms. Perhaps we assimilate information and make sense of our world in this latter half of the night. This could help explain a lower mood and mental capacity after a night of short or unrefreshing sleep!
Setting Up Your Day for Good Sleep
Clearly, our bodies operate according to naturally occurring biological rhythms. We need to work with these rhythms to optimize our sleep. The conditions for a great sleep can be created by keeping a few key concepts in mind.
Fundamentally, there is sleep drive and sleep rhythm. Sleep drive accumulates the longer we are awake, making us ready for sleep again after somewhere around 16 hours of wakefulness. Sleep rhythm describes how the body prefers to sleep consistently during a certain part of each 24-hour day (nighttime for most of us). Sleep efficiency is the ratio of total sleep time to time spent in bed with the intention to sleep on a given night. Sleep specialists deem 85% or above to represent a good sleep efficiency.
A good night’s rest starts in the morning. A consistent wake time is the most effective way to establish a robust sleep rhythm. As much as we may want to sleep in on weekends, varying wake time by no more than an hour can be helpful if you are trying to improve your sleep. Expose yourself to bright light and exercise early in the day to further reinforce your circadian rhythm and get your body sufficiently tired and relaxed to sleep at the end of the day. Taking in a nutritious first meal may also provide the body with cues that will reinforce this rhythm.
Sleep hygiene refers to things we can do in the evening to set ourselves up for a good night’s rest. A good wind-down is critical for preparing the body for sleep. We are not an appliance that can be turned on and off with a switch. Depending upon what you find to be relaxing and effective, a wind-down can include any of the following:
- Dimming lights around the house
- Listening to soft music
- Taking a shower or Epsom salt bath
- Writing in a journal
- Reading in quiet (paper book or nighttime/dark mode if using a device)
- Spending time with a pet
You may have noticed that, for instance, you are a night owl while your partner is a morning person. Although you can influence this to an extent, your body has a genetically determined period of time during a 24-hour day when it prefers to sleep. It is common in our culture to believe that “the early bird gets the worm”; however, the night owl trying to impersonate the early bird only puts himself at risk for health and safety issues!
There are 4 different chronotypes as identified by Dr. Michael Breus, a well-known sleep psychologist and author of the book The Power of When, reflecting different biologically based sleep preferences. In general, a lion is a morning person. A bear, which represents most of us, is a middle-of-the-day person who tends to sleep between 11PM and 7AM. A wolf is the proverbial night owl. A dolphin may keep bear-like hours, but tends to be a light sleeper as dolphins sleep with half of the brain awake! Which one do you identify with? Take this quiz through Dr. Breus’s website to identify your chronotype. It is best to honor your own chronotype as much as possible by building your daily schedule to accommodate it.
There are numerous factors across different categories that can sabotage sleep. Physical health conditions may include chronic pain, sleep apnea, dementia, Parkinson’s disease, digestive disorders like reflux and irritable bowel syndrome, menopause symptoms, and pregnancy. Make the effort to educate yourself. Talking to a doctor or other qualified health professional about improving sleep with any of these conditions is highly recommended. Review medications that you take with your prescribing doctor to help trouble-shoot sleep problems as well.
Symptoms of mental health conditions like anxiety, depression, and bipolar illness can include difficulty sleeping or early-morning awakening. Going through a stressful period in your life can absolutely trigger sleep problems as well. Consider talking to your doctor and good therapist or coach for help and support in managing these situations.
Elements of your physical surroundings and environment can be responsible for diminished sleep quantity or quality as well. Temperature, noise, light, an uncomfortable or worn-out pillow/mattress, a partner’s snoring, young children, and pets can be the culprits of sleep problems.
Keeping your sleep environment around 65 degrees may help with sleep. Address ambient noise, whether due to traffic or others in the house, by talking with others in your household, wearing good earplugs, or using a white noise machine, fan, or sleep music through headphones. Ask your snoring bed partner to turn on her side or schedule a doctor appointment to evaluate for possible sleep apnea; and/or sleep in another bed in the house if available. Bed partners with different sleep schedules should make efforts to honor each other’s individual sleep needs. Communication around this issue can go a long way to preserve both your sleep and your relationship!
Avoid backlit devices and blue light in general within the hour before bed or use blue-blocking glasses. Wear an eye mask to block out any ambient light. Avoid caffeine within at least 6 hours of bedtime. Avoid or minimize alcohol especially in the hours before sleep. As a depressant, it may help you fall asleep, but as it wears off in the middle of the night there is a rebound effect of physiological stimulation which can interfere greatly with sleep. Ideally, leave at least a couple hours’ time for digestion between dinner and bedtime; however, if you tend to wake up hungry at 3AM, have a small snack of complex carbohydrates before bedtime.
Insomnia and Other Sleep Disorders
Although we tend to casually throw the term ‘insomnia’ around to describe perceived sleep problems, chronic insomnia means that we have trouble falling or staying asleep for 3 nights a week for at least 3 months. In sleep onset insomnia, we have trouble falling asleep. Sleep maintenance insomnia reflects trouble staying asleep. Early-morning awakening, which tends to be associated with depression, is waking up several hours too early, causing us to miss out on sleep that we really need.
Primary insomnia means that the insomnia itself is the problem. Secondary insomnia is insomnia that is the result of some other factor, such as stress or a physical condition. Research suggests that Cognitive Behavioral Therapy for Insomnia (CBT-I) is 70-80% effective for primary insomnia.
Sleep apnea occurs when we have episodes in which we stop breathing through the night. This can be a serious problem and is associated with cardiovascular problems. Restless leg syndrome can also be included in the list of sleep disorders and may reflect overstimulation of the central nervous system. All of these disorders can be diagnosed and treated effectively by a qualified health professional such as a sleep specialist.
Medications & Supplements
If appropriate, your doctor may prescribe medications to help with sleep problems. A few classes of these medications are antidepressants, hypnotics, benzodiazepines, orexin receptor antagonists (inhibiting wakefulness), and melatonin receptor agonists. Medications can also help to manage any chronic pain to protect your slumber. Diphenhydramine, the active ingredient in Benadryl, is a common over-the-counter medication used to induce drowsiness for sleep.
Watch for medications that have known addictive tendencies. Keep in mind that sedation is not the same as sleep, and choose meds that preserve your sleep quality by allowing for a healthy sleep architecture. Arm yourself with good information and aim to use medication to help you sleep as directed by your doctor for the minimum time needed to get your sleep under better control.
There are a number of supplements you can use to support good sleep. Make sure you communicate with your doctor about this, especially if you already take medication(s), to avoid negative drug interactions. Melatonin helps with sleep timing as our bodies naturally produce it after nightfall. Magnesium is a calming mineral that can be taken in the evening. There are many good sleep-supporting teas containing natural ingredients like valerian, lemongrass, passionflower, and chamomile that you may opt to have after dinner.
Time to Let Go
I hope you have learned some helpful information that will aid you in optimizing your asleep in this post. If you are anything like me, your head may be swimming as you try to distill and apply potentially useful ideas in your life. Try to avoid becoming overwhelmed, thinking that you have to change everything at once. Choose 1 or 2 things that make sense to you and can be easily applied. You can move on to incorporate more as you find you can sustain what you have already tried, or have tried something and find that it just doesn’t work for you.
The irony is that, if we overthink sleep, this can negatively affect it! At a certain point, we need to decide to just let go of trying to control it all. We can just return to the body and breath (with a longer exhale, of course!), trusting in the body's innate intelligence and natural wisdom. The body knows how to sleep. Sometimes we just need to move out of the way!