Before we discuss sleep and your immune system, let’s have a quick review of what the immune system is. Your immune system protects you from germs. This system of cells, proteins, and organs work together to keep you healthy and prevent infection. When infectious organisms invade your body, your immune system mobilizes to attack them – this is called your immune response. When your immune system becomes compromised, you get sick.
Your immune system has a hard job to do. In large part, it’s able to do its job well because you get sufficient sleep. But getting good sleep often depends on being healthy.
Keep reading as we explore the cyclical relationship between your immune system and sleep-wake cycle.
How Does Sleep Loss Affect Your Immune System
Anyone who’s ever had a newborn, gone to college, or just had a late night on the town has probably suffered from sleep deprivation. Even if you miss out on a few hours of sleep, you feel groggier, more irritable, and have trouble focusing the next day. Both short-term and severe sleep loss have substantial effects on how well your immune system functions.
People who get less than 5 hours of sleep are nearly 5 times likelier to have a cold than those who get their recommended 7 hours or more, according to a study in the Journal SLEEP. They tracked healthy men and women via sleep trackers for 1 week, while exposing them to rhinovirus (the scientific name for the common cold) – the ones who slept less got sick more. Another study of identical twins who slept different amounts showed that the twins who got less sleep had a more compromised immune system. Reduced amounts of overall sleep, and lower sleep efficiency, also correlates with compromised immune systems and an increased likelihood of catching the common cold, according to yet another study.
Long-term lack of sleep, on the other hand, corresponds with higher rates of diabetes, obesity, and cardiovascular disease. And severe sleep deprivation – 24 hours or more of continued wakefulness – wreaks havoc on the immune system, according to multiple studies:
- A small group of men who went without sleep for 29 hours experienced a huge boost in their white cell blood count, mirroring the body’s reaction to physical stress response.
- Those who were sleep deprived for 48 hours showed high levels of nitrogen in their urine, another extreme response the body takes when under physical stress.
- Individuals who went 39 hours without sleep, showed higher heart rates, variations in blood pressure, and increased pressure on their hearts.
Meanwhile, with these extreme amounts of sleep deprivation, your emotions go haywire, you focus as well as you would with .10 percent BAC in your blood, and you’re susceptible to microsleeps that result in drowsy driving accidents. The rule of thumb is that for every 24 hours you go without sleep, you experience a resulting 25 percent drop in performance.
Fighting Illness; The Healing Power of Sleep
Now that we’ve gone all doom and gloom, here’s the good news: sleep is a powerful healer when you’re sick. Just as lack of sleep has a powerful impact on how ill you become, it can be just as powerful in helping you recover. There’s a reason why everyone tells you to rest when you’re sick.
In a study of fruit flies, researchers infected both a sleep-deprived group and a non-sleep-deprived control group with bacteria. Both experienced increased amounts of sleep after infection, as one might expect. But, perhaps surprisingly, the sleep-deprived flies had a better survival rate. They slept longer than their non-sleep-deprived counterparts, in what researchers called an “acute sleep response.” The results like these led them to believe that sleep is a natural response for survival.
In another study, rabbits were infected with E. coli and other infectious diseases, and then their sleep patterns were studied. Like the fruit flies, the rabbits who had the best survival rate slept longer during recovery, indicating that increasing your amount of sleep during recovery can lead to better recovery overall.
What accounts for the increased sleep when you’re ill? Researchers have found that your sleep architecture actually changes to aid in your recovery. Cytokines and neurotransmitters in your brain – the ones that regulate sleep when you’re healthy – increase when you’re sick.
Some researchers believe that these changes are designed to induce fever, which helps with your ultimate recovery. Since your sleep-wake cycle is connected with your body temperature, changes to sleep might facilitate the fever working its magic. In order for the fever to start, you need to shiver and maintain a higher body temperature. But shivering doesn’t occur during REM sleep, and your body temperature actually drops during NREM sleep. To help you recover when you’re ill, your body spends less time in REM, allowing shivering to occur, and your NREM sleep is fragmented, helping minimize that heat loss and aid in fever.
Lack of Sleep and the Flu
Just as lack of sleep makes you more susceptible to the common cold, it also compromises your immune system when it comes to the flu. Sleep deprivation lowers your T cell count while increasing inflammatory cytokines. As a result, your immune system isn’t as good at attacking intruders, while it’s better than ever at inflammation, creating the perfect environment for the flu virus to thrive.
Sleep deprivation also lessens the effectiveness of your flu vaccine. Sleep deprived individuals have more compromised immune systems, so they take 3 to 4 weeks longer to benefit from a flu vaccine, and are at risk of contracting the flu during that time. Worse, the vaccine may even trigger flu-like symptoms.
Even when vaccinated, sleep deprived individuals produce fewer vaccine-inducing antibodies overall and are less likely to have full protection against the disease. A study of college students with chronic insomnia showed they had lower antibody accounts for the H1N1 virus and two flu strains. The same researchers are currently conducting a study on hospital nurses, since they’re required to get yearly flu vaccinations to keep patients from getting sick, but experience sleep difficulties of their own.
This vaccine problem extends beyond the flu. Researchers have found similar results for hepatitis B vaccines and their effectiveness for sleep deprived individuals.
8 Hacks for Sleeping with a Cold or the Flu
Now you know that sleep is critical to a successful recovery from the cold or flu. If you find yourself sick this winter season, here are some tips to help you get a better night’s sleep. You’ll note that most of these are about relieving the sinuses and clearing the airways so you can breathe easier and enjoy more restful sleep.
- Use a vaporizer or humidifier to moisturize the air and alleviate your dry airways. Keep it clean so it doesn’t trap infectious mold or bacteria.
- Drink and eat hot liquids and foods like soup to clear dried-out airways and loosen up the mucus.
- Drink throat coating teas with honey or honey cough drops to provide relief for your sore throat and help clear the airways.
- Consider taking night-time cold and flu medicines that make you drowsy, such as a cough suppressant or cough syrup. Check with your doctor first to ensure they won’t interfere with any other medications you’re taking, and avoid ones with ephedrine or pseudoephedrine since those contain light stimulants that may keep you awake. Avoid sleeping pills, too, as these sedatives may interact negatively or cause an overdose when combined with the sedative ingredients in night-time cold medicines.
- Take a hot shower or bath before bed. Not only will the steam clear up your airways, the resulting drop in body temperature as the water evaporates from your skin will cool your body down for sleep.
- Prop yourself up slightly with a few pillows so gravity helps relieve sinus pressure and prevent mucus buildup while you sleep.
- Open up your airways before bed with vaporub, nasal strips, or nasal spray. Use a neti-pot or make your own saline rinse to loosen up mucus in your nose. Gargle with warm salt water to relieve your throat.
- Rock your vomer bone back and forth. This is the bone behind your nose. Follow the video below to help clear your sinuses.
How to Boost Your Immune System If You’re Not Sleeping Well
Even when you’re not sleeping well, there are some ways you can boost your immune system. Who knows, you may start feeling so good that you start to sleep better, too!
- Exercise regularly. Exercise makes your stronger and boosts your energy levels. If you can exercise in the morning, or outside in the sun, that’s even better. It will energize your body for the day, and make you tired enough by nighttime so you can fall asleep easily.
- Speaking of sunlight, spend time outdoors or sit by windows. Your sleep-wake cycles are heavily dependent on how your body perceives light. As the sunlight does down at night, you’ll be more inclined to sleep. Vitamin D deficiency is also correlated with reduced immune function, so take a vitamin D supplement or spend more time in natural light to boost your levels.
- There are many antiviral herbs you can take with food, as supplements, or in herbal teas that help prevent viruses. Popular herbal immune boosters include elderberry (shown to prevent flu), echinacea, ginseng, calendula, garlic, ginger, and olive leaf.
- Probiotics have also been shown to stave off cold and infection. You can find probiotics in yogurt, miso soup, kombucha, and supplement form.
Conclusion and Additional Reading
Lack of sleep makes you likelier to get sick, and reduces your body’s ability to enjoy the benefits of vaccines. Consistently not getting enough sleep (7 to 8 hours for adults) increases your risk of getting sick in the short-term and contracting the flu or the common cold, but it also spells real trouble for your health in the long run.
Not getting enough sleep increases your risk of obesity, diabetes, heart disease, and various autoimmune diseases. Learn more at the links below:
- Natural News explains how the interplay of hormones during periods of insomnia or hypersomnia contributes to obesity.
- The National Sleep Foundation reviews how chronic sleep deprivation affects your insulin levels and increases your risk for type 2 diabetes.
- A study published in the journal SLEEP studies how sleep disorders correlate with higher risks of autoimmune diseases including systemic lupus erythematosus, systemic sclerosis, Sjogren’s syndrome, and rheumatoid arthritis.
- A review of health workers who occasionally work 24-hour shifts revealed that the lack of sleep contributed to higher heart rates, blood pressure, and cortisol levels.