Headlines declare “Our Greatest Enemy? Inflammation” and “Inflammation in Midlife Tied to Brain Shrinkage Later in Life.” Scary stuff. But what exactly are they talking about?

We often mention inflammation without really explaining the nitty-gritty of it.

Acute, short-term inflammation is your friend: It signals that your immune system has been called into action to fight off invading viruses and bacteria (or to help heal an injury). Here’s the drill: Sentinel cells, alert your immune system when invaders appear. Then other cells cause your capillaries to leak blood plasma to envelop and slow down the invaders.

Next, macrophages release cytokines. These are germ fighters that are then joined by your B- and T-cells, which KO the invaders. And then, when the hordes are vanquished, more cytokines are released that signal the battle is over.

Without an acute inflammatory response, you would get ill from every passing germ, and a cut or scrape could turn lethal.

Chronic inflammation causes disease instead of fighting it. For a variety of reasons, the body can get caught in a state of persistent low-level inflammation.

When that happens, your immune-­system warriors cruise around your body even when there is no bacteria to fight off or injury to heal. Without specific targets to attack, they begin to damage organs, nerves and arteries.

What causes chronic inflammation? Obesity and a sedentary lifestyle are two identified culprits. Excess fat cells (particularly in the belly) trigger the release of those inflammatory first responders, the cytokines.

In addition, chronic inflammation is stoked by a diet packed with inflammatory foods, such as red meats and added sugars and syrups; lack of exercise and sleep; environmental assaults from air pollution; toxic chemicals; hormone disruptors; and the use of tobacco, marijuana, and hookah and vaping parlors.

SIGNS OF CHRONIC INFLAMMATION

Are you all-over achy, often fatigued, have irregular poop (either constipation or diarrhea), bloating, high blood pressure, weight gain? These can be signs that your immune system has gone rogue. Ask your doctor for a hs-CRP blood test to evaluate inflammation.

LIFESTYLE CHANGES TO MAKE

Opt for seven to nine servings of fresh fruits and veggies daily; get 900 mg of omega-3 DHA (helps lower background inflammation, according to a Stanford University study), aim for seven to eight hours of restful sleep nightly, get moving with both aerobic exercise (five days a week) and strength building (two days). Start meditating for 15 minutes daily. And be smart about avoiding potential toxins in plastics and receipts (phthalates and BPA), household cleaners, garden pesticides, water (use a home filter) and air. That should help put out the flame.

Mehmet Oz, M.D., is host of “The Dr. Oz Show,” and Mike Roizen, M.D., is Chief Wellness Officer and Chair of Wellness Institute at Cleveland Clinic. Email questions to youdocsdaily@sharecare.com.