Most people have experienced the effects of a good night’s sleep on your body’s ability to fight a sickness. When it comes to your health, sleep is your armor.

Research shows that people who are sleep deprived, or consistently miss out on quality sleep, are not only more likely to get sick after being exposed to a virus, but their bodies take longer to recover when they’re hit with an illness.

While stocking up on sleep can’t always prevent you from getting sick, it’s a key way to ensure your body is armed and ready to defend against what comes its way.

If you’re looking to give your immune system some extra support, here’s what you need to know:

Your Defenses Are Weaker If You Cut Corners on Sleep

Oftentimes, we write off sleep as expendable. According to current estimates, anywhere from half of the US population to two-thirds of all adults in developed nations aren’t getting enough sleep. However, one of the many consequences of losing out on sleep is a weakened immune system.

Research shows that individuals sleeping 6 hours or less a night were more than 4 times more likely to catch a cold compared to those who were logging 7+ hours of sleep. With every hour of sleep lost, the risk of catching a cold continued to rise.

Anything else I should know? Well, skipping out on sleep has also been shown to impact the effectiveness of one of the most important illness prevention techniques we have: vaccines.

Another study showed that people who slept fewer than 6 hours, on average, were far less likely to show the antibody response a vaccine is designed to trigger. Sleep deprived individuals were 11.5 times more likely to be left unprotected by the vaccine than people who were getting 7+ hours of sleep.

As sleep and immunity research continues to grow, it’s become clear that sleep deprivation puts your body at a disadvantage. When you get quality sleep, you empower your body to use every part of your immune system to battle any incoming or present threat. Don’t let your body head to the battlefield unprepared.

Your Immune System Ramps Up While You Sleep

Along with regulating your sleep, your body’s network of internal clocks helps manage your immune system and signals for it to kick into high gear while you’re asleep.

Although your immune system functions throughout the day, nighttime represents a unique opportunity for it to act while you aren’t interrupting it with meals, movement, or tasks. Your immune system requires a lot of energy to power its activities, so it takes advantage of reduced demands from the rest of your body during sleep.

As your immune system ramps up its nightly activity to defend your body, all that fighting releases chemicals, some of which cause inflammation. As a result, you tend to experience stronger symptoms—including fever, congestion, body aches, or sore throat—when your immune system is hard at work. Sometimes feeling worse at night, or first thing in the morning after all this activity, is a sign that your body is working harder to help you get better.

In addition to ramping up nightly activity, your immune system changes its strategy as well.

Your Immune System Changes Tactics at Night

Your immune system’s reactions are incredibly complex and have led to a growing field of research. What we already know is that your system is made up of a complex team of cells and proteins that work together to keep foreign invaders (such as colds or flu) at bay.

At night, they go on the offensive and work together to raise your defenses:

  • Turning Up the Heat: Your body has the ability to create a fever to help fight infection by deliberately raising your body temperature to an inhospitable level for pathogens (invaders) to reproduce. However, this comes at a high energy cost. Even a 1°C rise in body temperature requires a 10–12.5% increase in metabolic rate. This makes nighttime the perfect opportunity to use fever tactics because your body has more energy resources available when you’re powered down for sleep.
  • Prioritizing Body Repair: Many illnesses cause your body to rearrange sleep stages to increase the amount of time spent in NREM (deep) sleep while deprioritizing REM. The benefits are two-fold. First, NREM sleep is primarily focused on body repairs, while REM is centered around cognitive benefits. A body at war needs more frequent repairs to recover. Second, temperature regulation is turned off during REM sleep and your body needs to remain in NREM longer in order to sustain a fever.
  • Releasing the messengers: Cytokines are a type of protein that act as the primary messengers of the immune system. They send signals throughout your body to orchestrate immune responses, turn on and off certain defense systems, and promote different phases of sleep. Cytokines are both produced and released during sleep, making it crucial for you to get shut-eye when you’re sick.
  • Supercharging the Attack: Specialized cells, known as T-cells, primarily work on the front lines, where they recognize and kill infected cells. Like some animals, certain cells hunt best at night. Research has shown that sleep helps increase T-cell’s ability to ‘stick’ to target cells—making them more effective and lethal.

Even when you’re lying in bed, these systems are hard at work fighting a battle on a cellular level. Understanding how hard your body is working can help you effectively prioritize sleep.

What Can You Do?

If you’re concerned and feel like you’re getting sick, keep an eye out for these signs of strain, and remember to compare them to your normal baselines:

  • Decrease in heart rate variability
  • Increase in resting heart rate
  • Increase in respiratory rate
  • Increase in body temperature

Keep in mind, even if you do start feeling under the weather, you’ll be able to bounce back faster if your body is well-rested. To promote better sleep, try out these tips.

You can also support your immune system by being mindful of your daily routine and giving it the fuel it needs to be prepared to take on any threat:

  • Stay hydrated
  • Stock up on immune-boosting nutrients (zinc, vitamin C, etc.)
  • Avoid alcohol
  • Eat a well-balanced diet
  • Make time for hobbies that reduce stress
  • Keep active

The beginning of flu season or the presence of a new illness may be out of your control, but by preparing your body to take on any looming threats, you are already a few steps ahead. Prioritizing sleep is key, and those 7+ hours can make all the difference in the battles your immune system fights for you.

 


References

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Evans, S. S., Repasky, E. A., & Fisher, D. T. (2015). Fever and the thermal regulation of immunity: the immune system feels the heat. Nature Reviews Immunology, 15(6), 335-349.

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