If you pay attention to health issues, you probably hear a lot about inflammation. Chronic inflammation has gotten a lot of attention in recent years as a major contributor to illness and disease.
But how much do you know about the relationship between inflammation and sleep? That relationship brings together two complex and fundamental of the body’s systems—the immune system and our need for sleep. Keeping inflammation in check has big ramifications for our health. Sleeping well may be one way we can guard against the unhealthful inflammation that’s associated with chronic diseases from cancer and heart disease to autoimmune disorders such as rheumatoid arthritis and others.
What is inflammation?
In talking with my patients, I realized that while most of them understand that excessive inflammation can be harmful, many don’t have a strong understanding of what inflammation is, or what it does. Inflammation is a natural, protective biological response from the immune system to fight off harmful foreign pathogens—bacteria, viruses, toxins—that cause illness and disease, and to help the body heal from injury. The symptoms of acute inflammation, including swelling and redness, fever and chills, pain and stiffness, and fatigue, are signs the body’s immune system is in “fight mode,” working hard to neutralize a threat.
We talk a lot about the dangers associated with inflammation. But the body’s inflammatory response is essential to our health and survival.
Problems with inflammation occur when this natural, protective response happens too often, or at the wrong times. Autoimmune diseases occur as a result of the body triggering an inflammatory response when there is no foreign threat present. Instead, the immune system’s pathogen-fighting cells attack the body’s own healthy cells and tissues. Multiple sclerosis, rheumatoid arthritis, and lupus are examples of autoimmune conditions that develop in part from an excessive, misdirected inflammatory response.
Chronic inflammation is also linked to the development of heart disease, stroke, diabetes and cancer—the major chronic and life-threatening diseases of our time. With chronic inflammation, the body’s immune system is in perpetual fight mode, activating disease-fighting cells that have no external threat to fend off. Over time, these fighter cells can attack, wear down, and cause damage to healthy cells, tissues, organs, and systems throughout the body, leading to chronic illness.
Sleep and inflammation are regulated by the same biorhythms.
In talking about sleep and the immune system, we’re tackling two of the most complicated processes of the human body. For all our scientific inquiry to sleep, there’s a tremendous amount we don’t know. Though it’s clear we need sleep to survive, scientists still don’t know why we sleep. The human immune system is tremendously complex, and scientists are still working to decode its operations, to understand how it works—and why things go wrong.
One thing we do know? Sleep, immune function, and inflammation share a common regulator. Our sleep is regulated by circadian rhythms, which drive hormones and other physiological changes that cause us to move back and forth along a continuum of sleep and wakefulness throughout the 24-hour day. Those daily sleep-wake cycles we move through without much thought? Our circadian rhythms are working behind the scenes to keep us on schedule. When circadian rhythms are out of sync, so is sleep.
Circadian rhythms also regulate our immune system, and with it, our levels of inflammation. When circadian rhythms are disrupted, so is normal immune function. We’re more prone to unhealthful inflammation, and more at risk for diseases, including metabolic disease, cancer, and heart disease.
One way to help keep circadian rhythms in sync is to maintain a consistent sleep routine. Our biorhythms thrive on consistency. Going to bed at the same time and waking at the same time every day reinforces the healthy circadian rhythms that govern both our sleep and our immune function, including inflammation.
Too little sleep triggers inflammation. So does too much sleep.
Scientists still have a lot to learn about the specifics of the relationship between sleep and inflammation. But there’s already a strong body of research showing that lack of sleep raises levels of inflammation in the body. Laboratory studies have tested acute, prolonged sleep deprivation—conditions under which sleep is restricted for 24 hours or more—and found this severe degree of sleep loss increases inflammation activity in the body. Scientists have also studied partial sleep deprivation, the kind of chronic, insufficient sleep that so many people experience in their daily lives. While the study results are mixed, many studies show this form of everyday sleep loss also elevates inflammation.