Changing Your Circadian Clock For Night Shift Work

No matter how you arrange your life, night shift work is difficult to manage. Whether you are a nurse, machine operator, oil rig worker, hotel staffer, or any number of other jobs that make up the millions of needed people working nights, you have the arduous task of trying to get enough sleep to be productive and alert on the job. Many who work nights do not get enough sleep, and there are many reasons for this, but with a bit of planning and understanding some of the science, it is possible to shift the phases of your circadian rhythm to match your waking hours.


We think of sleep deprivation in extreme terms. It is commonly thought of as something akin to a torture technique, used to break people down for interrogation purposes. There is history behind that belief, and logical, scientific reasons for why it is effective. However, extreme stereotypes like this are problematic, because they lead people to think that there’s no way they could be suffering from such a thing. You aren’t being forced into it. You have a choice. Well, yes and no. You can choose not to work a night shift job, but if your circumstances are such that the only job available to you to pay the bills is at night? Our society needs night shift workers, however. It isn’t a choice, and we need to stop glossing over the fact that we are subjecting willing workers to hazardous working conditions.

On average, we need 7-9 hours of sleep each night. Humans are variable of course, so a few of us only need 6 and others closer to 10, but for the sake of this article, let’s call the minimum amount of sleep you need as 7 hours. Some of you are likely looking at that number and thinking, “On a good day off I might get that.” Some of you count up in your head and reach 7 hours because you get 4 when you get home, 2 1/2 in the evening before work, and grab 30 minutes on your lunch break halfway through the night. Needless to say, that is not the equivalent of 7 straight hours of good sleep.

Your body goes through a cyclical pattern everyday, functioning differently and doing various tasks dependent on whether you are awake or asleep. You are hardwired for this pattern, meaning your brain is built to do it. When you disrupt this pattern, for instance, by staying up and working all night, your body doesn’t respond and act properly. You are making the machine function in a way it’s not designed for, therefore it is not going to be as efficient and it will be more prone to breaking. Just because you want to be awake at 3 a.m. doesn’t mean your body thinks you should. This mismatch can end up being what’s called a “circadian misalignment”. This misalignment can result in a number of issues affiliated with sleep deprivation, such as the following:

  • Sleepy driving. Get too tired and you sometimes can’t stay awake no matter what you try. You will “micro-sleep”, where you will fall asleep for a half second or two. Needless to say, if you are driving home in morning traffic, this can be disastrous.
  • Work-related accidents. You are at higher risk of injuring yourself or someone else at work due to a decreased ability to focus, concentrate, and react as quickly.
  • Long-term health risks. Be awake when your body wants you to be asleep disrupts the normal cycle gut health. Gut health is key to numerous elements of overall body health, and night shift workers are more prone to IBS and other intestinal problems, because the expected eating patterns and types of foods are not healthy. Also, your body doesn’t reset the sympathetic and parasympathetic nervous system in its normal way, hormone levels and other key neurochemical interactions don’t function normally, and you are more at risk for mental health issues. Finally, your body doesn’t get its normal rejuvenation period, which helps fight infections and abnormalities, raising the risks for things like cancer.


Circadian literally means “around a day”. It is the timeframe in which our body regulates itself. The natural processes our body go through each day have a regularity to them, a rhythm, as it were, that if we were able to maintain and adhere to on a consistent basis, would help us maintain optimal health, both physically and mentally. When we don’t, as can be seen above, problems can occur. This circadian rhythm is governed by the hypothalamus in the heart of your brain. It is the clock that sets the timing for various processes in your body. It’s main source of input? Photoreceptors in your eyes. Light is the primary trigger for your body to know when the rhythm changes. These light signals are what cue your brain to activate the release of melatonin to help you fall asleep after the sun goes down.

Another primary body process that ebbs and flows along with the circadian rhythm is your body temperature. It actually fluctuates by a couple of degrees over the course of the day, peaking in late morning to early afternoon and bottoming out in the early morning hours when one is typically in the deepest parts of sleep. This is why you may find you get the most work done from 10am-1pm and why you really struggle to stay awake in that 3-6 am timeframe before getting that “second wind”. These are your high and low points for core body temperature. It is when you are most efficent and when you sleep the best respectively.

When your life works against this usual body routine, your circadian rhythm gets knocked out of whack. This is termed “circadian misalignment”. For night shift workers, it’s a significant and real problem. This is what happens when you experience “jet lag”. So, think of night shift work as inducing a permanent state of “jet lag”. Needless to say, it’s not difficult to imagine a permanent state of “jet lag” being bad for your health. So, what to do about?

Our culture has developed many ways to deal with not getting enough sleep. There’s an entire industry dedicated to boosting your energy levels in order to fight through your natural low points or when you haven’t achieved enough rest. Social norms and pressures are one of the problems with sleep wellness. Much like how technology has made us more sedentary, affecting physical wellbeing, the need for 24/7 operation of certain elements of society, has made the sleep wellbeing difficult for many. Stimulants, naps, supplements, special lighting, are all things used to help people get through those low points of the circadian cycle, but it is a constant and continual fight against the body’s normal rhythm. The solution, ideally, is to shift our natural rhythm to better coincide with our activity.


Getting your clock to match your sleep is the most reliable way to reduce the issues around sleep deprivation. You can even measure it. As stated earlier, your circadian rhythm follows a 24 hour cycle, and a key component in this rhythm is your body’s core temperature. When your core temperature is at it’s lowest, is when you should be in your deepest sleep. The decrease in daylight and the subsequent increase in melatonin triggers this temperature drop. It happens on a pretty regular schedule too. About 7 hours after the onset of melatonin production, your core temperature will hit bottom. This is assuming normal behavior. Force yourself to stay awake, get bright light exposure, experience a sleep disorder such as sleep apnea, and you disrupt the pattern. Your job, in shifting your clock, is to push the pattern to fit when you want to sleep.

In order to shift your clock, you primarily need bright light and consistency. There are some other things that can help you along the way, but without these two, it will be very difficult to correct your clock. In the two graphs below, you will see the results from a study of those who maintained these two elements compared to a schedule that isn’t uncommon among night shift workers. The important element to note on the graph is how the minimum body core temperature changes, denoted by the red triangles.

What do you see? In the first, the sleep blocks of time are consistent and the temperature minimum shifts into the time when the person slept, not during work hours, like the person in the second graph, who slept short hours and took naps prior to work. The significant elements here are the regular sleep hours on both work days and off days, and the fact that the first person wore sunglasses on the way home from work in order to reduce the light. Another important element is the first person maintained a sleep schedule on their off days that placed the minimum temperature time within their sleep window. They overlap enough to maintain consistency. You can see that the minimum is in the first half of sleep on work nights and the last half on off nights. Fortunately, you have some wiggle room here. You can maintain healthy sleep as long as that minimum falls within your hours of sleep.


There are some additional steps you can take to help create this consistency in your sleep.

  1. Melatonin supplements. Under normal circumstances, your body produces melatonin to help you fall asleep, but when you are manipulating your clock, you can ingest it in pill or chewable form. If you are a night shift worker and sleep soon after getting home, take it upon finishing your shift. If you sleep later in the day, take 1-2 hours before you go to bed.
  2. Nutrition. There is a reason people who don’t sleep well are at higher risk for weight and intestinal issues. Your metabolism changes when you sleep. If you are awake and eating when your body wants to sleep, you are making it even more difficult to fall and stay asleep when you do want to. Eating well when trying to change your clock is really important. Prepare ahead and don’t eat crap foods during night shift work.
  3. Wear sunglasses whenever exposed to sunlight. Even a few minutes of direct exposure to the light of day after a night shift can delay your ability to fall asleep. Limit the exposure and invest in a decent pair of sunglasses. It’s ok to look cool at 7 a.m.
  4. Create a conducive environment for sleep. Make your bedroom sleep heaven. You can have fun with this one, but get shades and curtains to block all light, use a white noise generator to cover random environmental noise that might wake you, get a pillow and mattress conducive to how you sleep. Develop a “wind down” routine for the last 30 minutes or so of your day before bed and stick to it like glue. Turn off your phone. Your bedroom should be the most peaceful and comfortable place you know.
  5. Learn meditation. This can be as simple or complex as you choose to make it. Meditation is a broad, wide-ranging field with many levels, but there are some simple meditations you can learn to help you fall and stay asleep. If you have difficulty falling asleep at times, this can help a lot.
  6. Start a stress journal. This is not a diary. You can treat it as such if you wish, but the purpose of it is to physically note all the things that happened during the day or are happening currently in your life that stress you out. This isn’t a phone app process. It should be a literal pen and paper notebook of some kind. The actual act of writing down what stresses you has a positive effect on your brain. It will help you sleep.


The above suggestions and information are presented in a context-free environment. Any number of things in your life can make doing or following this advice difficult or near impossible even. Children and/or family obligations, physical limitations, finances, social life, they all can have an impact on your ability to sleep. You could have a sleep disorder like sleep apnea. It can all make sleeping in a healthy way difficult at best. Arm yourself with information. Let others around you know. Family needs to be on board and support the sleeping habits necessary to keep you healthy. Your work environment should be supportive, understanding, and accommodating of sleep issues. Many organizations that run 24 hours a day have little understanding of the issues, and thus do nothing about it, placing the burden entirely upon you. Be proactive! Your sleep is vital to your health.

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