Boost your immune system

Are you secretly sabotaging your immune system? Some common lifestyle habits can have a detrimental effect on your ability to fight off infections like colds and flu – as well as your overall resistance to chronic illness.

If so, you need a lifestyle tune-up. Replacing bad health habits with good ones can improve your immune system health. Check the list of immune system boosters and busters to see where you’re doing well – and where you could use some improvement.

Lack of exercise: Sitting at your desk all day can not only make you feel sluggish, it can leave your immune system sluggish, too. Studies show that regular, moderate exercise – like a daily 30 minute walk -- increases the level of leukocytes, an immune system cell that fights infection. Being inactive can weaken your immune system indirectly, too. A sedentary lifestyle can interfere with sleep quality at night and can lead to obesity and other problems that increase your risk of illness.

Eating foods high in sugar and fat: Consuming too much sugar suppresses immune system cells responsible for attacking bacteria. Even consuming just 75 to 100 grams of a sugar solution (about the same as in two 12-ounce sodas) reduces the ability of white blood cells to overpower and destroy bacteria. This effect is seen for at least a few hours after consuming a sugary drink.

Experiencing constant stress: Everyone has some stress in their lives. And short-term stress may actually boost the immune system – the body produces more cortisol to make ''fight or flight'' possible. But chronic stress has the opposite effect. It makes you more vulnerable to illness, from colds to serious diseases. Chronic stress exposes your body to a steady cascade of the stress hormones cortisol and adrenaline, which suppress the immune system.

Get more antioxidants in your diet: A diet rich in antioxidant vitamins and nutrients can boost immunity to help fight infection. Your body produces free radicals -- molecules that can damage cells. Antioxidants help neutralize free radicals so they can’t do any damage. Researchers believe that when the balance between free radicals and antioxidants is upset, it can contribute to the risk of developing cancer and heart disease, as well as age-related diseases.