Circadian rhythm disorders affect the timing of your sleep. When you have a circadian rhythm disorder, your body clock is not in alignment with the world’s clock. Your body is able to sleep but not at the times you want or need to. There are two explanations for these types of sleep problems. One explanation is that your body clock is not working properly. Disorders resulting from a dysfunctional body clock include delayed sleep phase syndrome, advanced sleep phase syndrome, irregular sleep-wake rhythm disorder, and free-running disorder.
The other explanation for circadian rhythm disorders is that your work and social obligations are misaligned with the external clock. Disorders resulting from this misalignment include jet lag and shift-work disorder.
We are going to focus specifically on advanced and delayed sleep phase syndromes in this chapter. These are the two most common circadian rhythm disorders to be confused with insomnia.
There is variation in when people are primed for sleep. None of these variations are problematic in and of themselves. If you can accommodate your body’s schedule and get restorative sleep, we consider your shifted schedule to be a preference, not a problem.
Problems arise when your body’s natural sleep window does not mesh with your life. For example, you may be sleep deprived because you have to be up and about when your body is primed to sleep, and you can only sleep for part of the time you have set aside for sleep. Or you may be sacrificing important parts of your life (for example, job opportunities or social engagements) to accommodate your body clock. If your shifted body clock is causing this kind of distress or discomfort, then we call it a circadian rhythm disorder.
If you prefer to go to bed early and get up early, we call you a morning lark. Elderly people are most likely to have this sleep schedule. As long as you enjoy this schedule and it supports your daily obligations, this is not a problem. It is your body’s preference. However, if this pattern is interfering with your life or causing sleep deprivation, you may have a circadian rhythm disorder known as advanced sleep phase syndrome. The name comes from the current timing of your sleep opportunity. The time during which you are able to sleep is advanced, or ahead of, what you would like it, or need it, to be.
Advanced sleep phase syndrome can look like insomnia of the early awakening type. You may push through the early hours of your body’s sleep opportunity to be on a “normal” schedule. When you finally climb into bed you fall asleep easily because your body is primed to sleep. However, your wake drive then pulls you out of sleep before you have gotten enough hours. To your body clock, the next day has begun.
If you prefer to go to bed late and get up late, we call you a night owl. Adolescents and young adults are most likely to have this sleep schedule. As long as you enjoy this schedule and it supports your daily obligations, this is not a problem. It is your body’s preference. However, if this pattern is interfering with your life or causing sleep deprivation, you may have a circadian rhythm disorder known as delayed sleep phase syndrome. The name comes from the current timing of your sleep opportunity. The time during which you are able to sleep is delayed, or behind, what you would like it, or need it, to be.
Delayed sleep phase syndrome can look like the type of insomnia marked by trouble falling asleep. If you have to wake up earlier than your body clock would prefer, it is natural to also try to go to sleep earlier, so that you can get the hours you need. Unfortunately, your body is not yet primed for sleep, so you lie awake until it is.
One way to treat advanced and delayed sleep phase syndromes is to arrange your life around your body’s natural schedule. Remember, a body clock that is out of sync with the external clock is not unhealthy or dangerous in any way. It is only a problem when it interferes with your life. If you are able to stop fighting it, this is a perfectly reasonable treatment!
What would you have to do to accommodate your natural rhythm? For example, would you have to request different work hours, or start to work for yourself instead of for others? Would you have to negotiate different responsibilities at home? Would you have to change what you do in your leisure time, because different social opportunities are available? Would you see certain people you care about less?
Now consider what you would stand to gain if you accepted your circadian rhythm as it is. Would it be a relief to stop fighting it? Would you get more restorative sleep? Could your sleep schedule complement your partner’s, or your coworkers’?
If you think you would gain more than you would sacrifice, you may want to try this approach to dealing with your body clock’s misalignment with the external clock. But what if accommodating your body clock would come at too great a cost?
Multiple strategies can help you shift the timing of your sleep schedule. These include behavioral therapy, light therapy, melatonin, and chronotherapy.
We use the components of CBT-I in a slightly different way when trying to shift your clock. The behavioral components of CBT-I are used not only to promote restorative sleep, but also to move the sleep cycle to a different time. Therefore you will be focusing not just on what behaviors you engage in to promote your sleep cycle, but also on when you are going to engage in these behaviors.
If you have advanced sleep phase syndrome, you will want to move your bedtime later in the evening and your wake time later in the morning. It will be easier for you to manipulate the time you go to bed: you can force yourself to stay up for an additional fifteen minutes, but you cannot force your body to sleep fifteen minutes later.
If you have delayed sleep phase syndrome, you will want to move your bedtime earlier in the night and your wake time earlier in the morning. It will be easier for you to manipulate the time you wake up: you can force yourself to get up earlier, but you cannot force yourself to fall asleep earlier.
Put your primary focus on the part of your sleep schedule that you have more control over. The other will hopefully follow. It is recommended that you shift your bedtime and wake time in increments of fifteen minutes every three to five days. We do not recommend that you make a drastic shift in your bedtime or wake time. Our bodies are built for gradual change.
For example, let’s say you have been going to bed at 2 a.m. and waking at 9 a.m. (for a total of seven hours’ time in bed), but want to sleep eight hours a night, going to bed at 10 p.m. and waking at 6 a.m. The first step is to set your alarm and wake at 8:45 a.m. You will have a target bedtime of 1:45 a.m. Use this schedule for three to five days. Then start to wake up at 8:30 a.m. and climb into bed at 1:30 a.m. Repeat this schedule for three to five days. Continue to shift in fifteen-minute increments until you reach your desired goal of 10 p.m. to 6 a.m.
Be mindful of when you do activities that are engaging. If you have advanced sleep phase syndrome, you will want to add engaging activities in the late afternoon and evening and remove them from the early morning hours. If you have delayed sleep phase syndrome, you will want to decrease engaging activities in the evening and add them to your mornings. This sounds easier than it is. There are lots of activities that are more activating than we initially realize. Return to the section “Stimulus Control Therapy: Detailed Instructions” in chapter 6 for a full review on how to replace activating activities with more calming options.
It is very important to routinize your schedule as much as possible. Whenever possible, exercise at the same time every day. If you can, time your exercise to occur at approximately four to five hours before your desired bedtime. If this is not possible, then add in an activity that will create core heat in your body approximately four to five hours before your desired bedtime. Climbing stairs or doing jumping jacks are examples. As little as five minutes is all you need to create a little heat in your body. This heat is in sync with the sleep cycle you are promoting.
Eat at least one meal at the same time every day. Consistent digestion will help you anchor the sleep cycle you are promoting.
Using sleep hygiene can be very effective to shift your sleep schedule. The goal is to provide your body with as many cues as you can to sleep at the time you want to be sleeping. Refer to chapter 9 for a full review of sleep hygiene.
Circadian rhythm disorders are also treated with light therapy. You may remember from chapter 2 that light is one of the main influences on sleep from our external world. Light cues your mind and body to be awake. Darkness cues your mind and body to sleep. Light therapy involves adding and blocking light at strategic times to encourage your body to shift its sleep-wake cycles. Light therapy is one of the most effective tools in shifting the time of your sleep cycle.
Your body is currently wired to fall asleep before your desired bedtime. What cues your body to be awake? Light. Therefore, it is important to provide light in the late afternoon hours. Get outside or use a light that mimics daylight between 3 p.m. and 6 p.m. This light will cue your body clock to stay awake for a longer period of time. After repeated exposure to light at this time, your body clock will shift the timing of your sleep to a later point.
You are also wired to wake up before your desired wake time. What cues your body to stay asleep? Darkness. Therefore, it is important to block light in the early morning hours. Remain in a dark or semidark environment until 5 a.m. This environment will send a cue to your body clock to stay asleep later. After repeated exposure to darkness at this time, your body clock will shift the timing of your awakening to a later point.
Your body is currently wired to fall asleep after your desired bedtime. What cues your body to fall asleep? Darkness. Therefore, it is important to increase darkness in the evening hours. You will want to (partially) block light between 6 p.m. and 9 p.m. This environment sends a cue to your body clock to initiate sleep. After repeated exposure to darkness at this time, your body clock will shift the timing of your sleep to an earlier point.
You are also wired to wake up later than your desired wake time. What cues your body to be awake? Light. Therefore, it is important to provide light in the morning hours. Throw open the curtains, get outside, or use a light that mimics daylight within the first hour of your desired wake time. This light sends the cue to your body clock to start your wake cycle. After repeated exposure to light at this time, your body clock will shift the timing of your awakening to an earlier point.
Not all lights are the same. The best light source is natural light. If you live in an environment that has ample sunshine, then you can use this invaluable resource. You can benefit from natural light by going outside or by sitting inside near a window. You do not need to face the sun or stare directly at the sun. You just need to be exposed to the light.
If you do not have access to natural light at the appropriate times, there are many options for artificial light. You want to look for bulbs or lamps that mimic natural light. This means an intensity of around 2500 lux. Recent studies indicate that using a light source below 2500 lux is not effective for shifting your sleep cycle (Dewan et al., 2011). These light sources are not expensive (around $40) and are readily available.
You may be tempted to buy a higher lux light. After all, bigger is better, right? This is not necessarily the case with this intervention. If you are exposed to too much light (5000–10,000 lux), it can have a reverse effect. Too much light can cause irritability, anxiety, and trouble sleeping. Therefore, we highly recommend that you start with the lower levels first. Track your progress before you increase the brightness of your light.
There are specific cases in which you do not want to use higher levels of light for your sleep. If you have bipolar disorder or a family history of bipolar disorder, please be very careful using light therapy. Too much light can trigger a manic episode. If you have any current problems with your eyes or are taking photosensitizing medications, you will want to avoid light therapy. About a third of migraine sufferers have adverse effects with light therapy. Having a seizure disorder is another contraindication. If you have any concerns, we strongly encourage you talk to your medical providers before using light for your sleep.
These same parameters hold true for determining the duration of your light exposure. More is not necessarily better. Historically, it was thought that a shorter exposure of high-intensity light was most effective. More recently, studies have shown that a longer period of moderate-intensity light may be more effective for circadian rhythm disorders (Dewan et al., 2011).
Prior to the invention of electricity, we had much lower levels of sleep disorders. Electricity is a wonderful addition to our daily lives, but can be an impediment to our sleep.
There are many accessible and cost-effective ways to block light. The most effective method is to turn off your lights. There is no confusion when it is dark. Your body knows this means it is time to sleep. You can put light-blocking curtains (or dark sheets or blankets) over your windows as needed. You can use an eye mask as needed.
Of course, you will not be asleep the entire time that you want to be in relative darkness. This means you will need some light even during these times. Choose low light as much as possible. You can install dimmer switches on your lights to turn them down. You can use lamps with twenty-five-watt bulbs instead of overhead lights.
Also choose lights that do not contain blue light. Blue spectrum light most closely mimics daylight. Human brains evolved with fire as the only source of light after sundown, and fire does not contain the blue wavelength of light. Blue light is found in standard, compact fluorescent, and LED light bulbs, flat-screen televisions, smartphones and tablets, and most computer screens.
Whenever possible we suggest you not use electronic devices when you are trying to be in darkness. Again, removing the light completely is the most optimal treatment. If this is not possible, there are alternatives. There are apps you can download to your devices that block the blue light. You can purchase orange gels that cover your devices, again blocking the blue light. You also can purchase sunglasses that are designed to block the blue wavelength of light. This is the most versatile option, as you can move from one device or room to another, with continuous protection from blue light.
Melatonin is a popular supplement for sleep. It is readily available and affordable. Most people use melatonin as a hypnotic. They take it at bedtime since melatonin can make you sleepy at higher doses. However, melatonin also can be used to advance your body clock if you take it early enough. Taking microdoses (0.3 to 0.5 mg) of melatonin several hours before the desired bedtime can help you shift your schedule earlier if you have delayed sleep phase syndrome.
However, we suggest that you proceed with caution if you decide to use melatonin. Melatonin, like any substance you ingest, comes with both benefits and risks. Melatonin is not regulated by the FDA, so quality and dosage are not monitored. Melatonin can interact with other medications and supplements you are taking. Not all people benefit from using melatonin. We encourage you to consult with your medical providers prior to using melatonin or other supplements.
Chronotherapy is a very specific treatment for delayed sleep phase syndrome. You may already be aware that it is easier to keep yourself awake when you are sleepy than it is to go to bed when you are not. As a result, it is often quite challenging for people to gradually shift their sleep schedule forward in the manner we suggested earlier. Chronotherapy takes a backdoor approach to manage this barrier. Instead of trying to move the sleep cycle forward, you move it backwards (later). You keep moving the cycle backwards until you have gone all the way around the clock! When your sleep cycle reaches the desired time point, you maintain the new sleep schedule.
This intervention is extremely challenging. During chronotherapy, there will be times when you are sleeping in the middle of the day and staying awake all night. This takes quite a bit of planning and strategizing. Chronotherapy should be done under the supervision of a sleep specialist. You deserve to have a knowledgeable clinician on your team if you are going to engage in this challenging treatment.
It is very important to know whether you are treating insomnia or a circadian rhythm disorder. Even the most carefully crafted, well thought-out insomnia program will not be effective if you are treating the wrong thing!
If you do have a circadian rhythm disorder, you may decide to accommodate your body’s natural rhythm. Or you may try to shift it. We hope that the tools in this chapter put you on the right track. However, if you are trying to shift your clock by many hours, then we strongly encourage you to work with a sleep specialist. This is a difficult condition to treat, and you will benefit from expert guidance.