Sleep and Your Immune System: What You Need to Know


There is a reason why “sick and tired” just rolls off the tongue. That’s because studies show that being sick and being tired go hand in hand.  Sleep deprivation suppresses your immune system, making you more susceptible to illness.  Being sleep-deprived makes us more likely to catch a cold. Studies have shown that those who chronically get less than seven hours of sleep a night are three times as likely to develop the common cold compared to those who routinely get eight hours or more of sleep according to Dr. Yvonne Chu, MD, a sleep medicine specialist at the VA Connecticut Healthcare System.

Here are five connections between sleep and immunity:

  • In a 2009 study, people sleeping less than 7 hours per night had a 3 times greater risk of catching a cold than those with 8 hours or more. Lack of sleep can also affect how fast you recover if you do get sick. Your body needs sleep to fight infectious diseases. Long-term lack of sleep also increases your risk of obesity, diabetes, and heart disease.
  • We all know that fatigue makes us crankier and easily inflamed, but it actually undermines a key part of the body’s inflammatory response—called cytokines— which are absolutely essential for fighting off infections. There’s evidence that people who don’t get enough sleep show higher levels of inflammation.
  • As exhaustion rises so does the risk of serious infection. In a study of 57,000 women, those trying to get by on less than 5 hours of sleep a night had a 50% increase in risk of pneumonia.
  • Several studies have found that sleep promotes a stronger immune response to vaccines—which improves our body’s immunological memory.
  • Sleep may also help our T cells better glom onto their target to fight infection, according to a recent study out of Germany.
Related:   Excessive Daytime Sleepiness: The Top Possible Causes

While sleep plays a critical role in immune function, the immune system also affects sleep in multiple ways. Infections can trigger various responses from the immune system, including a lack of energy and sleepiness. This is one of the reasons why people who are sick often spend more time in bed and sleeping.

Improving sleep often starts by focusing on your lifestyle- including diet and exercise, routines, and your sleeping environment. Taking ,  straightforward steps, such as having a consistent sleep schedule,a comfortable bed, and avoiding using cell phones and tablets in bed, can make it easier to get a good night’s sleep.

Bottom line? Sleep is one of the best things you can do to strengthen your immune system and protect your body from cold and flu.  Get your zzzz’s!


Dr. Harvey Karp

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