There are many reasons why we sleep. It allows us to grow, to repair, and to recharge, among many other functions. But one underrated aspect of sleep is its importance in maintaining the healthy functioning of our immune system.
Like many other essential functions of the body, sleep is required to keep the immune system running smoothly. Without sleep, our ability to stave off infections and disease decrease dramatically, as does our general immune response to a whole host of other potential ailments.
So what exactly happens to our immune system when we don’t sleep properly? Will a single all-nighter put you at an increased risk of getting sick? And how does burning the candle at both ends affect us on a long-term basis?
Read on to learn all about the relationship between sleep and the immune system, as well as how you can implement healthy habits to keep from getting sick.
Sleep and the immune system are deeply intertwined
The human immune system is an incredibly complex mechanism that must be properly maintained in order to do its job. Sleep is a fundamental part of that maintenance.
Over the last 25 years or so, breakthrough research revealed that there is an undeniable link between the quality of sleep and an organism’s ability to fight disease.
In a 2004 review of the literature in the science journal Nature, authors wrote that,
There is increasing evidence that sleep deprivation has detrimental effects on the immune response… sleep should be considered a vital part of the immune system and that there is a reciprocal relationship between sleep and immunity.Bryant, P., Trinder, J. & Curtis, N. Sick and tired: does sleep have a vital role in the immune system?. Nat Rev Immunol 4, 457–467 (2004)
The article goes on to cite several studies on both animals and humans that suggest the following conclusions:
- In humans, sleep deprivation results in decreased immune-cell counts and functioning, as well as cytokine production (an important set of cells related to regulating the immune system).
- Patterns of sleep change when we are actively fighting an infection. Evidence suggests that cells that play a role in immune system regulation also play a role in the regulation of sleep. Generally speaking, our immune system causes us to sleep more when we are sick.
- Short term sleep loss (a single night of lost sleep) is not as detrimental to the health of our immune systems as long term, chronic sleep loss. It is worse for us to get a few hours less sleep every night over a long period of time than it is to miss one entire night’s sleep.
- There is evidence that certain disorders that affect sleep, such as depression or sleep disorders like narcolepsy, are linked to significant changes in immune functioning.
The exact biomechanics of how sleep and the immune system are intertwined is extremely complex, and still under active investigation.
We know that cytokines, a class of cells created by and for the immune system, play a large role. Cytokines seem to be involved in the regulation of certain types of sleep as well—another literature review noted that they are linked to the onset of NREM sleep.
There is also some evidence that T cells, which are another key component of the body’s immune system, may regenerate over the course of a standard night’s sleep. One author of a study on the topic concluded that this was a reason why,
Even one night without sleep affects the adaptive immune system.
Sleep deprivation’s effects on immunity and rates of infection play out over massive populations
Another interesting, and scary, takeaway from Nature’s 2004 review was that the societal shift towards longer work hours meant less sleep, and as a result, significantly higher rates of infection for certain populations.
Over the last few decades in the US and beyond, the average sleep length and quality of sleep has dropped due to massive increases in working hours. This presents troubling implications for public health, especially considering the significant detrimental effects of chronic sleep loss on the immune system.
What you can do to boost your immune system through sleep
The bottom line is this: healthy sleep leads to a healthy immune system. Here are a few tips to keep you healthy and happy.
- Listen to your body: Your body will always tell you how much you need to sleep. Or at least it will tell you when you aren’t getting enough. Make sure to carve out more time to sleep if you are still feeling sleepy after what you thought was a good amount of sleep. Check out our article on how much sleep is the right amount if you want a guide. Also, keep in mind that naps can be lifesavers! Don’t hesitate to take a mid-afternoon snooze if your body is telling you to!
- Set a routine: Setting a specific time to go to bed and get up in the morning helps us regulate our sleep patterns and stay healthy in the process. The body is more likely to get the sleep it needs and move through the sleep cycle in a normal way when we keep a consistent sleep schedule. You may find that if you are consistently setting an alarm in the morning and forcing yourself into bed at the same time, within a week or so you will naturally adapt without the help of any technology at all.
- Maintain proper sleep hygiene: This one is pretty straightforward—make sure your nightly routine sets you up for a solid sleep. During the day, make sure you exercise, but not too close to bedtime. In the evening, avoid screens (artificial light), alcohol and heavy foods. Make sure your room is dark and cool, and try meditating before bed to clear your mind of anxiety.
- Pay attention to the seasons, and sleep accordingly: During spring, you may be more susceptible to allergies, and therefore should sleep a little extra to boost the immune system. This goes double for the Winter, when cold and flu season fully hits. Making sure you are getting the amount of sleep you need during the winter months is one of the most important things you can do to help prevent the onset of infectious diseases.