In 1952, the city of London was paralyzed for five days with a superfog that held sulfurous coal-burning pollution from homes and offices, making it impossible in some parts of town to see your feet as you walked (and coughed) down the street.

But the brain fog that often accompanies chronic illnesses like obesity, heart disease, dementia, depression, and diabetes isn't some passing haze.

Far too often — and for far too many — it becomes a persistent challenge to focus on daily tasks or work-related demands.

Now researchers think they know why: inflammation.

According to a study published in the journal NeuroImage, when your body battles a chronic disease, your immune system becomes too revved up and produces excess inflammation. That negatively affects neural networks in the brain that have a unique sensitivity to inflammation.

As a result, they cannot properly help you become and stay alert to what's happening around you.

Adopting an anti-inflammatory regimen and sticking with it may help lift your brain fog. Here's how:

• Eat an anti-inflammatory diet centered around the following: veggies and fruits, especially berries and cruciferous vegetables like broccoli; as well as fish, like salmon, which has omega-3s that damp down inflammatory C-reactive protein and interleukin-6; and nuts and olive oil. Then with your doctors permission, take 900 mg of DHA omega-3 supplements daily.
• Exercise daily. Twenty minutes of moderate aerobics reduces inflammatory proteins in the body by 5%. So every day make sure you break a sweat (though not too intense nor too prolonged) and increase your heart rate and breathing.
• Practice a stress-management technique, such as meditation or yoga, daily.