Most inflammation doesn’t start with an injury. It starts with your ordinary days.
The sleep you cut short, the hours in a chair and the stress that never lets up: each one keeps your immune system quietly switched on.
Chronic inflammation rarely has a single cause. It builds from a few everyday triggers, and food is only one of them.
Left running for years, that low-grade inflammation is tied to heart disease and diabetes.
By the end of this guide, you’ll know what causes inflammation in your body and which trigger to tackle first.
Acute inflammation comes from a short-term threat that clears, like an injury or an infection. Chronic inflammation comes from triggers that keep the response switched on, and most of them are habits you can change.
You can change:
- Excess body fat, especially around the belly
- What you eat
- Sitting most of the day
- Poor sleep
- Chronic stress and anxiety
- Smoking
- Heavy drinking
You can partly control:
- Infections that don’t clear, including gum disease
- Gut bacteria out of balance
- Air pollution and chemicals
You can’t change (but can work around):
What causes inflammation?
Inflammation is caused either by a short-term threat or by ongoing triggers that keep the response from switching off. An injury or an infection sets off the first kind.
The second kind matters more for your long-term health: chronic inflammation is tied to heart disease, diabetes and other leading causes of death and disability. It’s also tied to cancer, chronic kidney disease and fatty liver disease, and to autoimmune and neurodegenerative disorders.
Chronic means the response stays switched on at a low level for months or years. A blood test picks it up through C-reactive protein (CRP), an inflammation marker your doctor can add to your blood work. If you want to go deeper into what inflammation is and how the response works, that guide covers it in detail.
What causes acute inflammation
Injuries, infections and irritants or allergens set off acute inflammation. Cuts, sprains and burns are the classic injuries; a cold, the flu or an infected cut are the classic infections. This kind does its job and switches itself off once the problem clears.
Chronic inflammation is the kind that doesn’t switch off, and its causes come next.
Causes you can change
These causes are everyday habits, and they depend on you.
Excess body fat, especially around the belly
Fat tissue releases its own inflammatory signals, so carrying extra weight keeps your immune system quietly switched on. The link holds whether you measure weight or waist size.
A review that pooled 51 studies found higher body mass index went with higher CRP in adults and children. The same held for waist size and for the waist-to-hip ratio, so the fat around the middle matters too. The link was stronger in women.
Signs it may be yours: a waistline that has crept up over the years, clothes fitting differently at the middle or a doctor who has already mentioned your weight.
What you eat
A more inflammatory eating pattern goes with higher inflammation in your blood.
In a meta-analysis of diet studies, each point up on a score of how inflammatory a diet is meant about 10% higher odds of raised CRP. In another meta-analysis of 64 controlled feeding trials, mixed sugar sources that included sugary drinks raised CRP, while adding whole fruit lowered CRP and TNF-α, another inflammation signal in the blood.
The pattern behind those numbers is what an anti-inflammatory diet plan walks you through, and the list of foods that cause inflammation names the specific foods involved.
Signs it may be yours: most days run on fast food, soda or packaged snacks, and vegetables show up more as a side than a main.
Sitting most of the day
Long hours in a chair go with higher inflammation markers, and much of that link runs through body fat.
In one study of adults, people who sat about 7 hours a day had higher TNF-α, but the link faded once body fat was accounted for. Leisure screen time was tied to higher IL-6, another inflammation signal in the blood, even in people who exercised. That means screen time on the couch counts even when you train.
Signs it may be yours: a desk job, a long commute and evenings on the couch, with movement mostly limited to weekends.
Poor sleep
Disturbed or broken sleep goes with higher inflammation markers in the blood.
A review of 72 studies with over 50,000 people found that disturbed sleep went with higher CRP and IL-6. Very long sleep showed the same link. Short sleep was only weakly tied to CRP.
Staying awake on purpose in a lab didn’t raise the markers. The problem is disturbed sleep, not just short sleep.
There’s also a hidden version: sleep apnea. Across 15 studies with 1,297 people, CRP was higher in people with sleep apnea, more so with obesity and more severe apnea.
Signs it may be yours: waking up tired after a full night in bed, loud snoring or a partner who says you stop breathing at night. If that sounds familiar, ask your doctor about a sleep study.
Chronic stress and anxiety
Long-lasting psychological stress goes with more inflammation signals in the blood.
A review lists psychological stress among the conditions that promote long-term inflammation across the body. And a meta-analysis found higher levels of three inflammation signals, IL-1β, IL-6 and TNF-α, in people with anxiety disorders, traumatic stress or obsessive-compulsive disorder (OCD) than in healthy people. The clearest difference showed up in post-traumatic stress disorder (PTSD).
Signs it may be yours: deadlines that never end, a long commute in heavy traffic or tension that stays with you for weeks, alongside aches you can’t explain.
Smoking
Smoking sends irritants into your airways, and the immune response to them shows up directly in inflammation markers.
In adults from the Guangzhou Biobank cohort study, CRP and white blood cells rose from never-smokers to former smokers to current smokers, and more with heavier smoking. The encouraging part: the markers fell the longer people had quit.
Signs it may be yours: smoking now, or a history of smoking you’ve never fully connected with how you feel.
Heavy drinking
Drinking heavily for years goes with inflammation signals that keep rising over time.
In a study that followed people over 10 years, steady heavy drinkers had higher IL-6, and it kept climbing. Steady moderate drinkers, on the other hand, had lower CRP than non-drinkers and heavy drinkers. Don’t read that as a reason to start drinking; the finding doesn’t cancel out alcohol’s other harms.
Signs it may be yours: drinking most nights, or glasses that keep growing past what you planned. If cutting back feels hard on your own, bring it up with your doctor.
Causes you can partly control
These causes depend partly on you and partly on things like your gums, your gut bacteria or the air where you live.
Infections that don’t clear, including gum disease
An infection your body can’t clear keeps the immune response running, and the markers stay elevated as long as it does.
Gum disease is a common everyday example. Periodontitis was consistently tied to higher CRP, and treating it over several visits lowered CRP for up to six months.
A meta-analysis of randomized trials put the drop at about 0.69 mg/L at six months, most in people who started above 3 mg/L. That fall came from dental treatment alone, a sign that an unresolved infection can hold your markers up.
Signs it may be yours: gums that bleed when you brush, teeth that feel loose or an infection that keeps coming back. A dental check settles this one.
Gut bacteria out of balance
A review found that gut bacteria play a central role in chronic low-grade inflammation.
The same review describes two related kinds: inflammaging, the low-grade inflammation that builds with age, and metaflammation, the similar kind that overeating drives. The gut sits at the center of both.
Signs it may be yours: bloating, irregular digestion or a diet low in fiber and high in processed food.
Air pollution and chemicals
Fine particles in the air set off inflammation in your lungs, and it spills into your blood.
Environmental toxins are among the causes a review lists for long-term inflammation across the body. Fine-particle air pollution is one of them. A meta-analysis found that cutting fine-particle exposure, for example with air filters, lowered CRP and blood pressure. What you breathe shapes what your blood shows.
Signs it may be yours: living near heavy traffic or industry, or a commute where you can see or smell the exhaust.
Causes you can’t change (but can work around)
These causes don’t go away, and the changeable habits still add up on top of them.
Age and menopause
Inflammaging is chronic low-grade inflammation that builds with age.
For women, menopause adds its own push: pro-inflammatory messengers rise as ovarian function declines. Genes play a part too.
Signs it may be yours: inflammation markers that crept up over the years, or a perimenopause or menopause that arrived with new aches.
Autoimmune and other conditions
In autoimmune conditions, the immune system mistakes your own tissue for a threat and keeps attacking it. Rheumatoid arthritis, lupus, psoriasis and inflammatory bowel disease work this way, which keeps inflammation switched on.
Other conditions are tied to chronic inflammation too, including diabetes, fatty liver disease and chronic kidney disease. This cause needs medical treatment, so work with your doctor on it. Diet can still be part of the plan: if you want a structured option to discuss, the autoimmune protocol (AIP) diet is one to bring up.
Signs it may be yours: joint pain with visible swelling, skin rashes that come and go or digestive flares your doctor has already linked to an autoimmune condition.
How to tell which cause is behind yours
There’s no single test that names the cause. A blood test can show that inflammation is raised, and the pattern of your days and symptoms points to the likely trigger.
If you have a recent result, inflammatory markers like CRP tell you how much inflammation is active, not where it’s coming from. The symptoms of inflammation add what you can feel. Each cause’s clues show in how you sleep, eat and move, and the table lines them up next to what to ask your doctor.
| Cause | Clues in your day | What to bring up with your doctor |
|---|---|---|
| Excess body fat | Waistline that has crept up, clothes tighter at the middle | Weight and waist check; talk about weight-loss options |
| What you eat | Fast food, soda or packaged snacks most days | Mention your usual eating pattern; ask about a dietitian |
| Sitting most of the day | Desk job, long commute, couch evenings | Talk about your activity level and heart health |
| Poor sleep | Waking tired, snoring, broken nights | Ask about a sleep study |
| Chronic stress and anxiety | Unending stress, ongoing tension, unexplained aches | Talk about mental health support |
| Smoking | Smoking now, or a long smoking history | Ask for help quitting |
| Heavy drinking | Drinking most nights, more than planned | Liver check and an honest conversation about drinking |
| Infections that don’t clear | Bleeding gums, returning infections | A dental check for gum disease |
| Gut bacteria out of balance | Bloating, irregular digestion, little fiber | Mention your digestive symptoms |
| Air pollution and chemicals | Living near heavy traffic or industry | Ask what it means for your heart and lungs |
| Age and menopause | Markers that rose over the years, new aches in menopause | Bring up menopause and what your age means for testing |
| Autoimmune and other conditions | Swollen joints, rashes, digestive flares | Tests for autoimmune conditions |
Take the clues to your doctor. For what lowers inflammation once you know the trigger, see how to reduce inflammation.
Frequently asked questions
Can stress cause inflammation?
Chronic stress can cause inflammation. A review lists psychological stress among the conditions that promote long-term inflammation across the body.
A separate meta-analysis found higher inflammation signals in people with anxiety disorders, traumatic stress or OCD.
Can anxiety cause inflammation?
Anxiety disorders come with higher inflammation signals in the blood.
In a meta-analysis, people with anxiety disorders, traumatic stress or OCD had higher IL-1β, IL-6 and TNF-α than healthy people, and the clearest difference showed up in PTSD. That doesn’t mean every anxious day raises your markers, but long-lasting anxiety is worth addressing.
Does sugar cause inflammation?
Sugar from drinks and mixed sources raises inflammation markers. In 64 controlled feeding trials, mixed sugar sources that included sugar-sweetened drinks raised CRP, while adding whole fruit lowered CRP and TNF-α.
The guide to foods that cause inflammation names the other sources worth checking.
What causes high inflammation in the body?
A high CRP usually points to an active infection or injury, or to an inflammatory condition such as an autoimmune disease. It can also come from several everyday triggers stacking up: body fat, diet, poor sleep and stress.
No single reading names the cause, so a doctor visit is the way to find out which one applies to you.
What is the main cause of chronic inflammation?
There’s no single main cause; in most people it’s a mix of the changeable triggers. Excess body fat and an inflammatory diet are among the most common in the research, along with inactivity, poor sleep and stress.
Finding your own combination is what tells you where to start.
