Sleep occupies one-third of your life — and for good reason. The time you spend counting sheep is necessary to support your mental, physical and emotional health. If you don't get enough sleep, something is bound to suffer, and it might just be your immune system.
Your immune system is your body's main line of defense against sickness, and its relationship to sleep is a two-way street. When your immune system is responding to an illness, infection or injury, it can affect how well you sleep. However, without an appropriate amount of sleep, your immune system can become unbalanced and inefficient.
Sleep needs and patterns vary depending on many things, including age, genetics and environmental factors. But generally, adults who get a minimum of seven hours of sleep per night set themselves up for good health.
Missing the mark on sleep occasionally does not do much damage. But if you skimp on sleep time all the time, you may develop chronic sleep deprivation — and an immune system that is dysfunctional.
How sleep deprivation affects immune function
According to a study in The Journal of Immunology, not getting enough sleep can weaken your immune system, which may make you susceptible to sickness in the short- and long-term.
Poor sleep affects your immune system in several ways, including:
1. Makes you more susceptible to common illnesses
When you consistently don't get enough sleep, your body tends to produce fewer antibodies — the proteins that identify foreign invaders to be destroyed. When antibodies are low, bacteria, viruses and toxins are more likely to "slip by" your immune system.
Research suggests that adults who regularly get five hours or less of sleep are more likely to develop respiratory infections. Adolescents who only get six hours of sleep are at increased risk of common illnesses, including cold, influenza and gastroenteritis.
If you have a sleep disorder — which is commonly associated with poor sleep — you may also be at increased risk for certain illnesses. One study found that having a sleep disorder makes you 1.23 times more likely to develop herpes zoster virus — the virus that causes chicken pox and shingles.
2. Increases your risk for cardiovascular and metabolic disorders
Inflammation is your immune system's protective response to injury and infection. It involves the use of white blood cells and molecular signals (cytokines) to eliminate threats and initiate healing. While inflammation in response to an acute threat is protective, ongoing inflammation in the body can damage cells and increase the risk for disease.
When your body does not get enough sleep, it generates more inflammatory cytokines, which can lead to a chronic inflammatory state and increase your risk for inflammation-fueled diseases such as:
- Autoimmune diseases, such as rheumatoid arthritis
- Cardiometabolic diseases, such as hypertension and Type 2 diabetes
- Neurodegenerative diseases, such as multiple sclerosis and Parkinson's disease
The relationship between sleep and cardiovascular disease is critical at any age. A 2023 review of studies reports that getting less than six hours of sleep per night is associated with cardiovascular disease at all ages, but especially in adults ages 40 and younger.
3. Reduces your antibody response to vaccines
Just as sleep helps your brain retain memories, sleep also supports your immune memory. Your immune system needs that downtime to help it remember, recognize and react to harmful antigens (anything that triggers an immune response) it's encountered.
According to the National Sleep Foundation, getting enough sleep before and after a vaccination can help that vaccination work better in your body. Sleep allows the immune system to register the antigen introduced through the vaccine.
Remember, sleep consistency is also key for antibody production — and making up for a week of poor sleep with more sleep the next week does not count. According to the Centers for Disease Control and Prevention (CDC), even if you double your sleep the next week, your body still may not respond well to vaccines. In fact, your antibody production following a flu vaccine may be 50% lower than that of someone who got the recommended amount of sleep both weeks.
4. Raises your risk for cancer
Cancer can develop if your immune system is unable to destroy infected and diseased cells before they grow and spread. To fight diseases such as cancer, the immune system relies on natural killer (NK) cells, a type of white blood cell.
The CDC reports that just one night of really poor sleep — four hours or less — can significantly reduce NK cell activity. NK cells that aren't functioning at full capacity are associated with a 1.6 times greater risk of dying from cancer.
Prioritize your sleep to support your immune system
Getting the recommended amount of quality sleep every night is critical for your immune system and overall health. Tips to improve sleep include:
- Cut out habits that disrupt sleep, such as using technology in bed and consuming sugar, alcohol or caffeine close to bedtime.
- Pay attention to your sleep environment, making sure it is dark, cool and distraction-free.
- Set a bedtime and wake time to ensure you are getting the full amount of recommended sleep every night.
- See a health care provider to address any chronic or severe sleeping issues or disorders.
