Sleep and Inflammation: How They Affect Each Other

Sleep does more than restore your energy. It also keeps your immune system in balance. When sleep falls short, inflammation rises, and when inflammation stays elevated, sleep suffers. The two are closely connected, and problems with one often show up alongside problems with the other.

About 1 in 4 American adults deals with insomnia symptoms. Many also have elevated inflammatory markers in their blood. Researchers have spent the past two decades studying this overlap, and the connection is now well established.

The good news: improving one side of this equation tends to help the other.

What is inflammation?

Inflammation is the immune system's response to threats. When you're injured or fighting an infection, your body sends cells and proteins to protect the affected area and begin healing. The redness around a cut or the swelling of a sprained ankle — that's inflammation doing its job.

This short-term response is called acute inflammation. It resolves once the problem is handled.

Chronic inflammation is different. It occurs when the immune system stays activated without a clear threat to fight. Instead of healing, this persistent low-grade response gradually damages tissues, blood vessels, and organs. The process often happens silently, without obvious symptoms, until health problems develop.

Conditions linked to chronic inflammation include:

• Heart disease and stroke

• Type 2 diabetes

• Rheumatoid arthritis

• Alzheimer's disease

• Depression

• Certain cancers

Several factors contribute to chronic inflammation: long-term stress, poor diet, physical inactivity, excess body weight, smoking, heavy drinking, and not getting enough sleep.

Does poor sleep cause inflammation?

Yes. When you don't get enough sleep, your body produces more pro-inflammatory proteins and fewer anti-inflammatory ones. The balance shifts toward inflammation.

The immune system uses signaling proteins called cytokines to coordinate its responses. These molecules act as messengers, telling immune cells when to ramp up activity and when to stand down. Several cytokines are directly affected by sleep:

• Interleukin-6 (IL-6) triggers inflammatory responses throughout the body and plays a role in fighting infections. But when IL-6 stays elevated without an infection to fight, it contributes to chronic inflammation. Levels rise when you don’t get enough sleep.

• C-reactive protein (CRP) is produced by the liver when inflammation is present. Doctors commonly test CRP to assess inflammation because it's a reliable marker of what's happening throughout the body. Levels above 3 mg/L indicate elevated inflammation and predict higher cardiovascular risk, including an increased chance of heart attack and stroke.

• Tumor necrosis factor alpha (TNF-α) contributes to systemic inflammation and has been linked to insulin resistance and metabolic dysfunction. Like IL-6, TNF-α increases when sleep is inadequate.

A 2025 meta-analysis in the Journal of Sleep Research reviewed 35 studies on sleep and inflammation. Sleeping four to five hours for three or more consecutive nights significantly raised IL-6 and CRP in healthy adults.

The effects can occur with less dramatic sleep loss, too. Research from Mount Sinai School of Medicine found that reducing sleep by just 90 minutes a night for six weeks — going from seven and a half hours to six — changed immune cell behavior and DNA structure in ways associated with heightened inflammation.

Regularly sleeping six hours when you need seven or eight creates a cumulative inflammatory burden over time. The effects may not be obvious day to day, but they accumulate.

Do these effects reverse when sleep improves?

Not entirely, according to recent research.

In the Mount Sinai study, mice that experienced disrupted sleep were then allowed ten weeks of normal sleep to recover. When researchers examined their immune stem cells afterward, those cells still showed changes from the earlier sleep disruption. They continued producing elevated numbers of white blood cells, maintaining susceptibility to inflammation.

This suggests the immune system retains some memory of past sleep deprivation. The cellular reprogramming that occurs during periods of poor sleep doesn't simply reset once sleep improves. Addressing sleep problems sooner rather than later may help prevent lasting effects.

This doesn't mean improving sleep is pointless — better sleep still reduces ongoing inflammatory triggers and supports overall health. But it does suggest that chronic sleep deprivation carries consequences that extend beyond the period of lost sleep.

Also Read: Harvard Researchers Find that a Good Night’s Sleep Can Add Years to Your Life

Can inflammation cause sleep problems?

Yes. The relationship works both ways.

Inflammatory cytokines can cross into the brain and affect the systems that regulate sleep. People with higher levels of inflammatory markers consistently report worse sleep quality — taking longer to fall asleep, waking more during the night, and feeling unrefreshed in the morning, even after adequate time in bed.

Normally, inflammatory activity follows a daily rhythm. IL-6 peaks during nighttime sleep and falls during the day. This pattern allows the immune system to do maintenance work while you rest without interfering with daytime alertness and energy.

In people with chronic sleep problems, this pattern gets disrupted. IL-6 may peak during daytime hours instead, and overall levels stay elevated around the clock. This mismatch makes quality sleep harder to achieve and can leave you feeling tired even when you've spent enough hours in bed.

Conditions involving chronic inflammation commonly include sleep problems:

• Up to 70 percent of people with rheumatoid arthritis report significant sleep disturbance

• Inflammatory bowel disease comes with higher rates of insomnia, even during remission

• Psoriasis severity correlates with sleep disruption severity

• Most lupus patients experience fatigue and poor sleep quality

For people with these conditions, managing inflammation often improves sleep, and better sleep helps control inflammation. The two reinforce each other in both directions.

Also Read: Sleep Debt: What Does It Really Mean for Your Well-Being?

Are women affected differently?

Some research suggests women may experience greater inflammatory responses to sleep disruption than men, with larger increases in CRP and IL-6 following sleep deprivation. Women also have higher rates of insomnia overall, which may compound these effects.

The reasons for these differences aren't fully understood. Hormonal differences may play a role, as estrogen and progesterone influence both sleep regulation and immune function. More research is needed to clarify the mechanisms involved.

What are the health risks?

Poor sleep and chronic inflammation are each independent risk factors for serious health problems. Together, the risks compound.

Heart disease

One older study found that middle-aged adults sleeping less than six hours nightly had nearly three times the risk of developing heart disease. Sleep deprivation raises blood pressure, LDL cholesterol, and triglycerides — all factors that damage blood vessels over time. 

Inflammation accelerates atherosclerosis, the buildup of plaque in arteries that leads to heart attacks and strokes. The combination of poor sleep and elevated inflammation creates conditions that favor cardiovascular problems.

Type 2 diabetes

A 2024 study found that sleeping five to six hours doubled diabetes risk compared to seven to eight hours. Sleep deprivation impairs glucose handling and reduces insulin sensitivity, making it harder for cells to take up blood sugar effectively. 

These effects are partly mediated by inflammation — TNF-α and IL-6 interfere with insulin signaling at the cellular level, contributing to insulin resistance.

Cognitive decline

During deep sleep, the brain's glymphatic system clears metabolic waste, including beta-amyloid, a protein that accumulates in Alzheimer's disease. Insufficient sleep impairs this clearance process, allowing waste products to build up. Chronic inflammation damages neurons through separate pathways, contributing to cognitive impairment. 

People consistently sleeping less than six hours show faster cognitive decline over time compared to those getting seven to eight hours.

Depression

Elevated inflammatory markers appear in a significant proportion of people with depression, suggesting inflammation may play a role in the condition. Sleep problems both result from and contribute to mood disorders. 

A study of about 1,000 young adults found that those with insomnia were four times more likely to develop major depression within three years compared to those without sleep problems.

Weakened immunity

Your immune system depends on adequate sleep to function properly. People sleeping less than seven hours are nearly three times more likely to catch a cold after virus exposure compared to those getting eight or more hours. 

Vaccine responses are also weaker in sleep-deprived people, with fewer protective antibodies developing after immunization.

Also Read: Why Sleep Deprivation Can Lead to Serious Health Issues

What causes chronic inflammation?

Several factors keep inflammation elevated. Addressing them alongside sleep can help break the cycle.

Chronic stress keeps cortisol elevated. While cortisol normally helps control inflammation, sustained high levels cause tissues to become less responsive to its effects. Inflammation rises as a result. 

Stress also keeps the nervous system activated, interfering with the calm state needed for restful sleep.

Diet plays a significant role. Ultra-processed foods, refined carbs, added sugars, and fried foods promote inflammation and can alter gut bacteria in ways that increase systemic inflammatory responses. Anti-inflammatory eating emphasizes vegetables, fruits, fatty fish (salmon, sardines, mackerel), nuts, seeds, olive oil, and whole grains. 

The Mediterranean diet has the strongest evidence for reducing inflammation and has also been linked to better sleep quality.

Physical inactivity allows inflammation to build. Exercise reduces visceral fat, improves insulin sensitivity, and triggers the release of anti-inflammatory proteins from muscles. 

Prolonged sitting has the opposite effect; even people who exercise regularly show higher inflammatory markers if they spend most of their day sedentary.

Excess body weight, particularly around the midsection, actively produces inflammatory chemicals. Visceral fat functions almost like an endocrine organ, continuously releasing signals that promote inflammation. 

Even modest weight loss (5-10 percent of body weight) measurably reduces CRP and IL-6.

Smoking and heavy drinking both drive inflammation through multiple pathways and independently impair sleep quality. Alcohol may help you fall asleep initially, but it disrupts sleep architecture later in the night.

Also Read: Best Foods for Sleep: What to Eat and Avoid Before Bed

Does sleep consistency matter?

Yes. It's not just total hours; regularity matters too.

Going to bed at different times, waking at different times, and sleeping variable amounts creates internal misalignment. Your circadian rhythm coordinates immune function alongside sleep, and irregular patterns disrupt this coordination.

Research has found that people with inconsistent sleep schedules have higher inflammatory markers even when their average sleep time is adequate. The body seems to function best with consistent sleep schedules.

Keeping a steady schedule — same bedtime, same wake time, including weekends — supports both sleep quality and inflammatory balance.

How can you reduce inflammation and improve sleep?

Addressing both sides of the cycle typically works better than focusing on just one.

Keep a consistent schedule

Go to bed and wake at the same times daily, including weekends. Aim for seven to nine hours. If you've been keeping irregular hours, start by anchoring your wake time — your body will gradually start feeling sleepy at a more consistent hour. Consistency reinforces the circadian rhythms that coordinate sleep and immune function.

Eat an anti-inflammatory diet

Build meals around vegetables, fruits, fatty fish, nuts, olive oil, and whole grains. Limit processed foods, added sugars, and fried foods. You don't need to overhaul everything at once. 

Start by adding more anti-inflammatory foods like salmon twice a week or a handful of walnuts as a snack, then gradually reduce inflammatory ones. The combined effect of small changes adds up over time.

Move regularly

Aim for at least 150 minutes of moderate activity weekly — about 30 minutes five days a week. Walking, swimming, cycling, and resistance training all help reduce inflammation and improve sleep quality. 

Breaking up long periods of sitting also matters; even brief movement breaks throughout the day help. Avoid intense exercise within two to three hours of bedtime, as it can delay sleep onset.

Manage stress

A wind-down routine before bed helps with both stress and sleep. Dim lights an hour before bed, step away from screens, and try slow, deep breathing or gentle stretching. These practices don't just feel relaxing in the moment — studies show they measurably reduce inflammatory markers over time with consistent practice.

Limit alcohol

Alcohol may help you fall asleep, but it disrupts sleep quality in the second half of the night and increases inflammation. Cutting back, especially in the evening hours, benefits both sleep and inflammatory balance.

Consider a natural Sleep Aid

Some natural compounds have research backing for both anti-inflammatory effects and help with sleep.

Montmorency tart cherry contains anthocyanins, antioxidant compounds with demonstrated anti-inflammatory properties. Tart cherry also provides natural precursors to melatonin, which helps regulate sleep.

Venetron®, derived from rafuma leaf, promotes relaxation and helps reduce anxiety without causing grogginess.

Sip2Sleep® is a natural sleep aid that combines Montmorency tart cherry extract with Venetron® to address both the inflammatory and stress-related components of sleep difficulty. It's a melatonin-free option for those looking for natural alternatives to some over-the-counter sleep aids.

The bottom line

Sleep and inflammation influence each other directly. Poor sleep raises inflammatory markers, and elevated inflammation disrupts sleep. Over time, this cycle increases risk for heart disease, diabetes, cognitive decline, and other serious conditions.

The flip side: improving one tends to help the other. Consistent sleep timing, anti-inflammatory eating, regular physical activity, and stress management all address both sides of the equation. Natural options like tart cherry extract can provide additional support.

You don't need to change everything at once. Pick one area to start — maybe anchoring your sleep schedule or adding more anti-inflammatory foods — and build from there. Small, consistent changes add up.

Frequently Asked Questions

How much sleep do I need to keep inflammation down?

Most adults need seven to nine hours nightly. Consistently sleeping less than seven hours is associated with elevated inflammatory markers. Regularity matters too — a steady schedule helps maintain healthy inflammatory rhythms.

Can a few bad nights cause inflammation?

Short-term sleep loss can temporarily raise inflammatory markers, but levels typically normalize with recovery sleep. Chronic sleep deprivation over weeks or months produces more persistent changes that may not fully reverse.

Does inflammation cause insomnia?

It can contribute. Elevated inflammatory cytokines affect brain systems that regulate sleep, making it harder to fall asleep and stay asleep. People with chronic inflammatory conditions often experience insomnia as a result.

What foods help with both inflammation and sleep?

Fatty fish, tart cherries, walnuts, leafy greens, berries, and olive oil have evidence for anti-inflammatory effects. Several of these also support sleep. The Mediterranean diet benefits both.

How long does it take to lower inflammation through better sleep?

Some improvement in inflammatory markers can occur within days to weeks of better sleep. However, the longer the inflammation has been elevated, the longer it may take to see significant changes. Consistency over time produces the best results.

Does sleeping too much cause inflammation?

Some studies associate long sleep (more than nine to ten hours regularly) with elevated inflammation, though it's unclear whether excess sleep causes inflammation or whether underlying conditions cause both. Seven to nine hours is appropriate for most adults.

Will reducing inflammation help me sleep better?

Often, yes. Managing inflammatory conditions frequently improves sleep. Anti-inflammatory lifestyle changes also tend to improve sleep quality. The relationship works both ways.

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