You’ve felt it before: low energy, weakness all over and that unshakeable brain fog. It’s not your imagination. Skipping sleep takes its toll – and not just on your productivity at work. Sleep has strong ties to the body’s immune system. In fact, a 2009 study found those who slept five hours or less were 4.5 times more likely to catch a cold than those who regularly got seven hours of shuteye. Now, you might be thinking late nights and early mornings are, sometimes, inevitable – and they are. You could have a newborn to feed every couple hours or a big presentation to prepare. If you're wondering, "How does sleep help your immune system?", we're here to explain the different ways adequate sleep benefits your well-being, so you might work harder to avoid those all-nighters.

A Sleep Crash Course in Biological Clocks

Before diving into the details of sleep and your immune system, it’s important to have a basic understanding of biological clocks and to know what is circadian rhythm. Believe it or not, your body has several biological clocks – one in almost every tissue and organ. Within your tissues and organs, are cells, which also have their own molecular circadian clocks. These targeted clocks all have their own circadian rhythms, which are synced up by the master clock. The master clock is a system of about 20,000 neurons, forming what’s known as the suprachiasmatic nucleus (SCN). The SCN can be found in the brain’s hypothalamus, where it receives direct messages from your eyes. The messages sent to your SCN can speed up, slow down or completely reset your master clock and circadian rhythms. One of the most powerful messages is light. When the eye sees light, it tells the SCN to produce less of the sleep-inducing hormone melatonin. As a result, you wake up. In contrast, less light leads to more melatonin and a state of drowsiness. This is why the 24-hour dark/light cycle is so critical to the flow of circadian rhythms. To put it simply, timing is everything.

5 Ways Sleep Improves Immune System Function

1. Sleep affects immune system homeostasis.

Like all human processes, your immune system is controlled by its own circadian clock, as well as the master biological clock. When these circadian rhythms are all in sync and running smoothly with the 24-hour dark/light cycle, the immune system maintains homeostasis. Unfortunately, this schedule is easily disrupted by sleep-depriving factors, such as light exposure, shift work and jet lag. In fact, numerous studies have proven these specific sleep-depriving factors change natural circadian timing and lead to increased rates of cardiovascular disorders, metabolic syndromes and even cancers. The good news is adequate sleep can help regulate circadian timing. Listen to your body when it feels tired and do your best to maintain a regular sleep routine. You might try reading a book in bed, meditating or journaling. These are all good ways to signal to your body that it’s time to rest and reset your clocks.

2. Sleep promotes immune cell production.

Your body’s adaptive immune system is made up of key lymphocytes known as T cells and B cells. These are the cells that fight foreign invaders by directly killing them (T cells) or by developing antibodies (B cells) that protect you from their damaging effects. The production of these particular lymphocytes peaks during times of rest. This means that while you sleep, your immune system floods the blood with higher levels of adaptive immunity cells. As a result, your body is better able to process and recognize an antigen when it tries to attack your immune system.

3. Sleep orchestrates immune cell response.

Immune cells have their own molecular clocks, which are also influenced by time of day and patterns in your routine. This creates anticipatory immunity, which allows the immune system to respond to upcoming changes in its environment. Eating and sleeping are changes your molecular clock expects every day. As a result, your immune system gets used to these regular occurrences and knows how to respond to them. Since when you eat and when you go to bed helps determine immune cell response, it’s important to keep these factors regulated. If you can eat and sleep on a similar schedule every day, your immune system will be better prepared to take on an attack.

4. Sleep reduces stress levels.

You’ve probably heard this one before: chronic stress increases blood cortisol levels. What you may not have realized is that cortisol interferes with your body’s master circadian clock. While a burst of cortisol can actually improve inflammation in the short-term, letting it accumulate over time can lead to more inflammation. If your body is in a constant state of stress, increased production of cortisol will throw your clock out of homeostasis. Since your circadian clock helps regulate the immune system, this imbalance can negatively impact how quickly – and how many – immune cells spring to action. This dysregulation of the immune system puts you at an increased risk for several foreign invaders. The good news is you can reset your circadian clock very easily with adequate sleep. During stressful times, it’s especially important to get rest. This will allow cortisol to return to normal levels and your circadian clock to maintain its rhythm.

5. Sleep enhances vaccine effectiveness.

What did you do after your last flu shot? Most likely, you went back to work or school, with the hope that you were protected from the flu virus. Sleep was probably the last thing you were worried about, when it should have been top of mind. Studies on hepatitis and flu immunizations have proven that the number of hours you sleep after vaccination significantly correlates with an increased production of protective antibodies. According to one study, mice who were sleep deprived after receiving the flu vaccine “behaved as though they had never been immunized.” The next time you get a flu shot (or any vaccine), be sure to prioritize sleep in the days and weeks that follow. This will help your body build the most solid protection against the harmful pathogens.

Power Down With RestoreZ

Not everyone’s schedule can accommodate seven or eight consecutive hours of sleep. That doesn’t mean you can’t catch a break, though. Powering down for a midday nap can actually boost your energy, mental focus and creativity. Even just 20 minutes of restful napping can bring you back to life. Can’t hit the hay? RestoreZ Power Nap is a sleep nutrition supplement that provides the benefits of a nap without all the grogginess. If your body needs more than a power nap, RestoreZ offers a full line of comprehensive sleep supplements. Each formula is made with natural ingredients and is designed to restore your circadian rhythm for tip-top health. Remember, your immune system depends on you to power down every day. Besides, no one’s productive when they’re sick in bed. So which will you choose: sleep now or be sick later?