Sleeping on a consistent schedule is one of the healthiest and most important sleep habits you can have. Regular bedtimes and wake times are the foundation of a strong sleep routine. Consistency in sleep routines is the key to getting the right amount of high-quality rest to meet your individual needs—and ensuring those needs are met routinely. Consistency helps us avoid piling up a sleep debt, and can offer protection against a range of health conditions, including high blood pressure, high cholesterol and high blood sugar.
Consistent sleep routines also offer protection for mood and emotional health. We’ve all lived through a lot of turmoil in this past year, and it’s taken a big toll on emotional well being. We don’t talk enough about how much the consistency of sleep affects mood and emotional regulation. Sticking to a consistent sleep routine is an under-utilized tool in elevating and stabilizing mood in the short-term and protecting against mood disorders, including depression and anxiety, over the long term.
There’s some interesting new research out on this important topic, which shows how important the consistency of sleep routines is to maintaining emotional balance and regulating mood.
Inconsistent sleep patterns raise risks for depression
Scientists at the University of Michigan investigated the impact of sleep routines on day-to-day mood and on risk of depression over time, and their newly published results show that irregular sleep routines are as big a risk factor for developing symptoms of depression as being sleep deprived, and also have as much of an impact on daily mood as short sleep does.
The scientists spent a year gathering data on sleep and mood from a group of more that 2,000 first year medical residents. This is an excellent population to use to study the relationship of sleep and mood, especially in relation to consistency of sleep. This is a group who, in addition to working long and demanding shifts and often having to go without sleep, also work irregular schedules and face real challenges in sleeping and waking on a regular schedule.
The medical interns (aka first year residents) wore wristband trackers that captured data about their sleep and activity patterns, and they filed daily reports (via a smartphone app) about their moods. They also took tests every three months over the course of the year, to assess for symptoms of depression.
The researchers found that interns who had irregular sleep schedules had lower daily mood ratings. The irregular sleepers also showed more symptoms of depression at the quarterly check ins.
The scientists also looked at how the amount of sleep interns got affected mood and found that those who got the least amount of sleep and those who routinely stayed up late also had lower daily mood ratings and tested higher for depression symptoms.
When they compared the impact of irregular sleep routines and insufficient sleep on mood, they found that the effects were about the same, both for daily mood and for the development of depression symptoms over time.
There’s a large and often-talked-about body of research that links sleep deprivation to low mood and higher risk for depression. But the impact of consistency of sleep on daily mood and psychological health over time tends to get overlooked. This study shows us that consistency in sleep patterns may matter as much to emotional health as sleep amounts, in the short and long term.
The role of routine sleep in regulating mood
How can the schedule of our sleep have such powerful and direct influence over mood?
Irregular sleep routines disrupt circadian rhythms
Circadian rhythms affect mood in numerous and complex ways. Genes that control circadian rhythms (the so-called “clock genes”) have been shown to regulate mood and mood-related behavior, including behaviors associated with depression, anxiety, and bi-polar disorder. The brain’s emotion-regulating activity itself follows daily, 24-hour rhythms. And many hormones and neurochemicals that control and influence mood, and the body’s stress response, have their own circadian rhythms, including serotonin, melatonin, dopamine, cortisol, and norepinephrine.
In addition, circadian rhythms regulate metabolic chemicals that affect the anxiety and reward centers of the brain, including the hormones ghrelin and leptin, and a neuropeptide called cholecystokinin, or CCK, which has a strong influence over anxiety and stress.
Inflammation is increasingly thought to play a significant role in mood disorders, both by directly affecting mood and by contributing to the development of other health conditions that raise risks for depression and anxiety. (Inflammation also has a major impact on sleep itself.)
When circadian rhythms are disrupted, these critical mood and stress-regulating processes go awry. A large body of research shows that depression, anxiety, seasonal affective disorder, bi-polar disorder, and other mood disorders are strongly linked to disrupted circadian timing.
Our individual differences in circadian timing create our chronotypes. And our chronotype has a major influence on mood and emotional balance. Some chronotypes are at greater risk for depression, anxiety, and mood disruptions than others. Research tells us that people with late chronotypes—the Wolves of the world—are significantly more vulnerable to a range of mood disorders including depression and anxiety, and have greater difficulty regulating emotions, compared to early chronotypes (Lions). Night-wired Dolphins are also highly prone to anxiety—nighttime anxiety and mental tension (and naturally high nighttime cortisol levels) are part of what contribute to Dolphins’ difficulty falling asleep and getting refreshing sleep. And middle-of the road Bears are prone to irregular sleep routines and an accrual of sleep debt, which can raise risks for mood disorders.
The bottom line?
Any chronotype that lives out of sync with daily rhythms is vulnerable to the impact of circadian dysregulation on mood and emotional balance.
Do you know whether you’re a Lion, Bear, Dolphin or Wolf chronotype? Take this short quiz to find out: www.chronoquiz.com.
The consistency of your sleep routine has a great deal to do with keeping circadian rhythms running in sync. When we sleep and wake at the same times, day after day, we send powerful signals to our brain’s circadian clock and circuitry that keep our biological clock running “on time,” according to our individual biological timing. Sleeping and waking irregularly from day to day throws circadian rhythms off their natural timing, and increases our vulnerability to emotional stress, emotional reactivity, and mood disorders.
Inconsistent sleep schedules lead to sleep debt
A lack of sleep is a major driver of mood problems, emotional reactivity, and mood disorders. Going without sufficient sleep raises risks for depression, increases stress (and decreases our capacity to manage stress effectively), and elevates risks for anxiety disorders. There’s also evidence that gender may play a role in the impact short sleep has on mood, with women and girls more vulnerable to the negative mood effects of going without sufficient rest.
Sleep is a fundamental and critical time for the body to regulate mood; when we don’t get enough of it, it’s harder for our bodies to properly manage stress, and for us to maintain emotional balance.
One of the functions of sleep—particularly REM sleep—is to process emotional experiences, so that difficult emotional experiences feel less raw, intense, and emotionally charged. Scientific research has found that sleep “soothes” the brain of stress, lowering our emotional reactivity and increasing our capacity to think rationally and calmly about difficult experiences.
Sleeping on a routine schedule of regular bedtimes and wake times is one of the most effective ways to ensure you get sufficient sleep to meet your individual needs. We don’t all need eight hours of sleep every night—but most adults need at least seven, and many need more than that. Sleeping less than 6 hours a night, for most people, is likely to lead to a chronic sleep debt, and greater volatility and difficulty with daily mood, stress management, and emotional balance.
Sleeping irregularly also hinders sleep quality
When it comes to protecting emotional health and balance, sleep quality matters too. Research shows strong links between poor sleep quality , higher stress, and mood problems. And while we know that the relationship between sleep and mood is a two-way street, this recent research found that the next-day effects of poor sleep quality on mood were far greater than the effects of a day’s mood on the next night of sleep. Making sure your sleep is high quality and restful is as important as getting enough rest, to protect your emotional health.
Irregular sleep routines get in the way of achieving the high-quality sleep you need to feel rested, refreshed, and emotionally centered. Waking often during the night keeps you in lighter stages of sleep and diminishes your time in the deep and REM stages of sleep that provide the most significant restoration of your brain’s emotional circuitry, relax and refresh your central nervous system and its complex interplay with your immune system, and allow your hormones and neurochemicals to function on their optimal daily rhythms.
How to stick to a regular sleep schedule
Determine your optimal bedtime. For most of us, bedtime is the place where we have more flexibility, and that makes it the place to start in setting up a routine that you can maintain consistently. Our wake times are usually socially determined, by commitments to work, school, kids’ morning routines, even getting the dog outside for her morning walk. You can use my bedtime calculator to figure out your optimal bedtime. And this calculator helps you measure sleep quality in addition to sleep quantity, so you can be sure you’re getting the restful sleep you need in the right amount for your individual sleep needs.
Create a PowerDown Hour™ for your pre-bedtime routine. Consistency in sleep gets a whole lot easier when you create relaxing rituals that come before bedtime. On the flipside, if your pre-bed routines are all over the map, you’ll have a much harder time making it to bed on time every night. The PowerDown Hour™ should be relaxing, full of self-care, free of electronics and digital devices, and geared toward preparing you for a sound night of rest. That can mean different things for different people, and I encourage you to experiment with what the most restful rituals are for you. Here is a template to start building a simple, easy-to-stick to, sleep-promoting nightly routine:
Use 20 minutes for hygiene and grooming and taking any medications that you are supposed to take at bedtime.
Use 10 minutes each for:
Soothing your mind. Meditation is a great idea, but so is listening to some soothing music, a funny or inspiring podcast, or reading a book—with blue light blocking glasses if you’re using an e-reader.
Relaxing your body. A light yoga practice, tai chi, light stretching, a walk around the block with the dog before lights out are all great ways to release physical tension and relax your mind before sleep.
If you’re like me and you enjoy a shower or bath before bed, schedule your soak for 90 minutes before lights out in order to maximize its sleep-inducing benefits.
Satiating your stomach. My rules for a pre-bed snack are to keep it at about 250 calories, a balance of protein and complex carbohydrate, and to steer clear of the sugar-loaded snacks so many of us crave at night.
Engaging your senses. Creating a restful sleep environment is essential to making a bedroom inviting and sleep promoting. Go beyond the basics of quiet, dark, cool, and clean to engage your senses more fully in the transition to sleep. Essential oils can be potent sleep promoters by relaxing both body and mind. And you can use the power of touch to relax, de-stress, and elevate your mood before bed. Partners can take turns giving each other simple massages. You can also use self-massage practices, or the touch therapy practice of reflexology, which reduces brain wave activity and increases sleepiness.
Protect yourself against nighttime light. If you’re using devices at night—let’s face it, most of us do–use blue light blocking glasses in the evening to protect against exposure to bright, stimulating, blue-rich light. That way you can have your nightly Netflix or your social media scroll time and allow your body to make its natural progression toward sleep, on a consistent schedule that aligns with your individual circadian rhythms.
Commit. The longer you stick to a sleep routine, the easier it gets. Your body and mind will be primed to sleep and wake at the same time every day, supported by the pre-sleep routine you put in place. If it feels like work at first, dig in and stick with it! You’ll be amazed at how much more natural it feels after even a few weeks. And you’ll feel a real difference in your sleep and your emotional health.
Michael J. Breus, PhD, DABSM
The Sleep Doctor™