Waking up after a truncated night’s sleep is a feeling we all know too well. Groggy, crabby, and caffeine in hand, we find ourselves floating through the day without our usual stores of brainpower. But according to a new meta-analysis study, published in Biological Psychiatry, long-term sleep deprivation can do more than make us fatigued and irritable. Turns out, it can also cause physical changes in our brains and bodies and contribute to a host of chronic diseases and mental health issues.
Researchers examined scientific literature on the link between lack of sleep and inflammation, just one of the identified side effects of sleep deprivation. Based on a review of 72 reports, which involved more than 50,000 participants from population-based and clinical studies, they concluded that getting too little or too much sleep resulted in increased inflammation levels.
“It is important to highlight that both too much and too little sleep appears to be associated with inflammation, a process that contributes to depression as well as many medical illnesses,” said Dr. John Krystal, editor of Biological Psychiatry, in a press release.
Sleep disturbances (like waking up several times throughout the night) or having insomnia were examples of poor sleep. Getting less than, or more than, 7-8 hours of sleep per night has been shown to result in increased levels of inflammatory markers in the blood, like C-reactive protein (CRP) and interleukin-6 (IL-6). These markers have been linked to chronic diseases like heart problems, hypertension, and type 2 diabetes, suggesting that poor sleep is a behavioral risk factor for inflammation, in line with high fat diets or sedentary lifestyles.
“Together with diet and physical activity, sleep health represents a third component in the promotion of health-span,” said Michael Irwin of UCLA, an author of the study, in the press release.
Past studies have mirrored the latest findings. In 2015, researchers found that sleeping too much or too little increased low-grade inflammation as well as a person’s risk of depression and diabetes. And women with heart disease may be at the biggest risk of sleep-related inflammation, a 2013 study found.
Inflammation is an immune response to fight infectious agents or injuries, but “it also contributes to the pathophysiology of many chronic diseases,” a 2007 study states. In other words, inflammation can protect the body, but in certain cases it can cause harm. Plenty of chronic diseases are associated with inflammation, including asthma, inflammatory bowel disease, rheumatoid arthritis, and even certain types of cancer. Even depression has been linked to inflammation, though researchers still continue to investigate the mechanisms that are involved in inflammatory diseases.
Scientists now agree that there seems to be a clear association between poor sleep and inflammation, though more research will be needed to understand that relationship. It may have something to do with impaired immune system function, or many of the other effects of poor sleep on the body. To protect yourself from sleep deprivation, maintain a clean sleep schedule that allows you to get 7-8 hours of sleep every night.
Source: Irwin M, Olmstead R, Carroll J. Sleep Disturbance, Sleep Duration, and Inflammation: A Systematic Review and Meta-Analysis of Cohort Studies and Experimental Sleep Deprivation. Biological Psychiatry, 2016.