Why is the switch from night shift to day shift so difficult?
Transitioning from night shift to day shift is one of the most challenging aspects of shift work, especially when that switch is required within a twenty-four hour period.
Whereas the switch from days to nights requires staying awake and lengthening your day, this switch requires you to shorten your day. As the human clock runs slightly longer than twenty-four hours, lengthening your day is the more natural of the two. It’s simply easier to stay awake longer than it is to will yourself to sleep when your body is not ready.
It is the equivalent of flying across twelve time zones in an eastward direction (assuming twelve-hour shifts). And as anyone who has done a lot of flying will tell you, westward travel is the easier adjustment.
How can we make the switch from night shift to day shift easier?
Just like there’s no cure for jet-lag, there’s no foolproof method for what we’re attempting to do here. You’re unlikely to feel one-hundred percent no matter what you do.
That said, if you’re having trouble making this transition, following these guidelines will help you adjust as quickly as possible, while greatly reducing the misery.
Wear blue-light-blocking-glasses during your night shift
Artificial light at night (ALAN) has a profound effect on our circadian rhythms. I’ll provide some tips for reducing exposure at home later in this post. But to make the transition to dayshift easier, you’ll also want to avoid blue light while working night shift.
This is because ALAN has a carry-over effect. In this two-night study, participants were exposed to light from midnight til 2 AM on night one. This light suppressed melatonin by up to 81%. On night two, the participants weren’t subjected to any light at all, yet melatonin onset was still delayed up to 36 minutes.1
And this was after only two hours of light exposure; not an entire eight or twelve-hour shift.
Unfortunately, there’s usually not much you can do about workplace lighting. This is where blue-light-blocking glasses come in. A quality pair can protect you from the harmful effects of ALAN, without affecting job performance.2
I like the Sleep+ glasses from BLUBlox for their superior protection. If your work requires safety glasses, try the UVEX Skyper.
Nap at work
Any amount of sleep you can get during your last night shift will reduce the amount you’ll need when you get home. Napping at work helps you minimize sleep debt and also serves as a synchronizer of circadian rhythms.3,4
Depending on your work environment, on-shift naps can be controversial. If your workplace won’t allow naps, it’s worth asking if there’s an opportunity to group break times together. For example, I’ve heard from nurses who used this strategy to enable a forty-five minute window for sleep.
Using breaks for sleeping instead of snacking becomes much easier when coupled with time-restricted eating.
Limit sleep after last night shift
Limiting sleep leads to higher concentrations of adenosine in the brain, increasing the drive to sleep. There are two methods of achieving this:
Stay up all day
I’ll preface this by saying I don’t subscribe to this method, for reasons I’ll get to below. However, it has been bandied about as a good tactic for getting back to a normal routine as quickly as possible, and will most certainly make it easier to sleep that night.
Suffer through the inevitable brain fog and exhaustion before heading to bed earlier than normal to limit sleep debt.
This is a fast way to adapt, but given how often I switch between days and nights, it leaves me too prone to accumulating a large sleep debt. Not to mention how terrible I feel after staying up so long. But if you’re still having trouble adjusting after following the other recommendations, this tactic is worth a try.
Get up early
Since discovering the existence of the ninety minute sleep cycle, I’ve been using this as a guide to planning my initial sleep after finishing my last night shift. Upon getting to bed, I set my alarm for four and a half hours from then (three complete sleep cycles) plus twenty minutes to allow for the onset of sleep.
This specific length of time may not work for everyone, but I have found it to be the best balance between being able to function that day and being able to sleep that night. If you’re still having difficulty getting to sleep that first night, try cutting your post-shift sleep to three hours (two sleep cycles) or experiment with the “stay up all day” method.
Limiting sleep debt by sleeping in the morning, when other family members are at work or school, also allows me to maximize family time in the evening. Staying up all day has me either extremely irritable, or in bed before everyone else, missing out on things like family dinner and bedtime stories.
Note: If following this strategy, it is a good idea to wear driving approved, blue-blocking sunglasses on the way home from work (assuming the sun is up). This will prevent the sun light from advancing your melatonin rhythm, allowing you to get to sleep easier when you get home. An inexpensive option fitting this criteria is anything with the Espresso lens from UVEX
Limit caffeine, or forgo it altogether
The best piece of advice to give here is avoid caffeine entirely. Caffeine has a half-life of five to six hours. If you have a cup at two o’clock, to combat the afternoon slump, half of that caffeine may still be in your system six hours later. You may not feel like you drank half a cup of coffee at eight o’clock, when you should be winding down for bed, but the caffeine is still present and will have a negative effect on your sleep.5
I’ll sometimes follow my own advice, but I love coffee and still like to drink a cup on that first day off after night shifts.
If my coffee addiction gets the better of me and I decide to have a cup, I’ll “cut” my normal coffee with decaf
Which brings me to my next point. If you are going to have caffeine that day, have it as early as possible.
Note: Since the caffeine content is minimal, or at least lower than normal, the energy boost may partially be attributable to the placebo effect – an effect more helpful to the coming sleep.
Get some sunlight
Expose yourself to sunlight that day, as early as possible. Preferably at least thirty minutes but the more the better. Light is the biggest synchronizer of circadian rhythms. Exposure early in the day will help reset your body’s clock and act to improve energy and mood.6
Couple this with physical activity for maximum benefits.
Significant light exposure during the day will also decrease the negative effects of artificial light after nightfall7, improving your chance of quality sleep that night.
Melatonin supplementation
As I noted above, I subscribe to the “get up earlier” strategy in regards to coming off night shifts. Compared to staying up all day, this can make it more challenging to get to sleep that night, particularly if I worked a number of night shifts in a row. To overcome this, I sometimes supplement with melatonin, a hormone that signals to the body that it’s time for sleep
Melatonin normally rises in the evening, shortly after nightfall, inducing drowsiness. If you’ve worked a number of night shifts in a row, your natural melatonin rhythm has been thrown off. The rise of melatonin will occur much later than required for traditional sleep hours. Similar to its use in combating jet-lag, supplemental melatonin can help by increasing concentrations at a more natural time.
You need less than you probably think – 0.5 to 2 mg should be adequate. You may have to do some searching because melatonin is more commonly sold in 3, 5 and 10 mg capsules. Start with the lowest dose you can find to avoid next-day grogginess. Many brands provide tablets that are scored down the middle, allowing you to split them and take a half dose.
Melatonin is cheap. With prices as low as $0.03 per tablet
Exercise, but not too late
Morning is a great time for exercise, especially when coupled with sunlight exposure as mentioned above. But since I go to sleep as soon as I get home from night shift, I’ve found the afternoon works best. The afternoon is also when cardiovascular efficiency and muscle strength are highest8, making it ideal for intense exercise sessions.
Intense exercise has been shown to increase adenosine concentrations in the brain9, increasing the drive to sleep. Daytime exercise has also been shown to lower cortisol levels at night.10,11 As cortisol is the body’s “stress hormone”, you want levels to be low for good sleep.
However, you don’t want to exercise too close to your desired bed time. Exercise leads to short-term spikes in heart rate, body temperature and the aforementioned cortisol, all of which make sleeping more difficult. You want to leave enough time for these effects to subside – at least two or three hours.
Note: As you’ll probably have some amount of sleep debt, this may not be the best day to go for any PR’s.
Meal timing
In addition to light, meal timing is also an important synchronizer of circadian rhythms. As such, eating in accordance with your desired rhythms will facilitate a faster adjustment.
Eat at normal dayshift meal times and don’t eat two to three hours before bed.
For example, if you get up at eleven o’clock and normally eat lunch at noon, don’t eat “breakfast” right away. Wait until the next normal meal time to eat. Then if you want to be in bed by nine that night, try to eat your last bite of food by six, or seven at the latest. This strategy is also popular for minimizing jet-lag (wait to eat meals at normal local times, even if your hunger suggests otherwise).
Eating late into the night sets off bodily processes, such as digestion, at a time when these processes should be shut down. This can cause your core body temperature to rise, leading to greater difficulty falling asleep. Late night eating also increases your risk of acid reflux.
Note: For more information on meal timing and other aspects of circadian rhythms, I highly recommend Dr. Satchin Panda’s book, The Circadian Code
Avoid artificial light after nightfall
Avoid bright lights for two to three hours before bed, especially blue light. At this unnatural time, blue light suppresses melatonin and delays circadian rhythms.12
Avoiding light at night is challenging in today’s environment. Not only are newer lighting sources more harmful from a circadian rhythm perspective, but many of us also spend a huge portion of our day looking at the LED screens on our computers, smartphones and tablets.
To reduce the risk of melatonin suppression and make it easier to get to sleep, employ these tactics:
- Dim the lights or use task lighting such as lamps instead of overhead lights.
- Use blue-light filtering software if you must use electronic devices; Night Shift for Apple products, Night Light for Android, or download F.lux for devices that don’t have the feature built-in.
- For extra insurance, or when blue light is unavoidable, wear glasses that filter out blue light. Two good options are the popular Swannies by Swanwick Sleep
, or my personal choice, Sleep+ by BLUBlox.
- If you have money to spare, you can go all-out and fit your home with smart lighting from Philips Hue
For more information on the benefits of blue-light-blocking glasses and how to select an effective pair, check out Why every shift worker needs blue-light-blocking glasses.
Avoid alcohol
It’s tempting to turn to alcohol for its sedating effect, but as neuroscientist and sleep expert Matthew Walker regularly points out, sedation is not sleep. Even a small amount before bed will have a negative effect on your sleep quality. Though alcohol allows you to lose consciousness more quickly, it leads to shorter, more fragmented sleep.13
Note: Matthew Walker’s book, Why We Sleep
Other considerations
Whether you stay up all day or shorten your post-shift sleep, you’re still likely to experience the negative effects of sleep deprivation.
On that first day off, don’t schedule or plan to do anything that requires optimal cognition, because you are almost guaranteed not to have it. This is especially true for anything involving emotional intelligence, as even mild sleep loss can make us moodier and less empathetic.14
Save things such as learning new skills and important conversations for another day.
The next day
When switching from night shift to day shift in twenty-four hours for work, your schedule will require getting up early the following day. If, however, the next day is another day off, you’ll still want to get up early to ensure quick adjustment to day mode. This will likely require an alarm, as your circadian clock is still adapting. Again, expose yourself to sunlight as early as possible and maintain timing of meals, exercise, and light exposure in accordance with your natural circadian rhythms.
Summary - or rules to follow for a quick transition
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Wear blue-light-blocking glasses at work and, if possible, have a nap during your last night shift
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Limit post-shift sleep so you’ll be tired at bedtime
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Avoid caffeine
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Expose yourself to sunlight, as early as possible – at least thirty minutes
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Exercise, but not too close to bedtime (afternoon is ideal)
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Eat at normal dayshift meal times and avoid eating two hours before bedtime
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Avoid bright lighting after nightfall, especially blue light
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Avoid alcohol
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Try supplementing with melatonin before bed if you’re still having trouble after implementing the above strategies
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Save things such as learning new skills and important conversations for another day
Featured photo by Tomasz Woźniak on Unsplash
- https://www.ncbi.nlm.nih.gov/pubmed/ll763987[↩]
- doi.org/10.1210/jc.2004-2062[↩]
- ncbi.nlm.nih.gov/pubmed/15732300[↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC3627437[↩]
- https://www.ncbi.nlm.nih.gov/pubmed/24235903[↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC3630978[↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC6212492[↩]
- ncbi.nlm.nih.gov/pubmed/25645125[↩]
- ncbi.nlm.nih.gov/pubmed/18031936[↩]
- ncbi.nlm.nih.gov/pubmed/10200900[↩]
- ncbi.nlm.nih.gov/pubmed/27956050[↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC4284776[↩]
- ncbi.nlm.nih.gov/pmc/articles/PMC4666864[↩]
- ncbi.nlm.nih.gov/pubmed/25117004[↩]