STEP 1 Get moving 行动起来

Get moving: Just 30 minutes a day of moderate exercise will do. You can even split it into three 10-minute bursts of activity.

STEP 2 Laugh it off 每天笑一笑

Find something to laugh about every day – even force it if you have to. Real or fake, laughter strengthens your immune system by increasing good-for-you hormones and reducing stress ones; lowering your blood pressure; and slowing your resting heart rate.

STEP 3 Look at the bright side 往好的一面想

Train yourself to look at the bright side. Optimistic people were two and a half times less likely to develop cancer of any kind than their pessimistic peers, according to one study.

STEP 4 Make time for friends 留出时间与朋友交往

Make time for the friends you have and cultivate new ones. A study found that seniors with a lot of pals were 22 percent less likely than their less social counterparts to die during the decade when they participated in the study.

Start a bridge group. Research shows that bridge boosts the body's defense against infections and illness.

STEP 5 Eat well 好好吃饭

Eat a healthy diet: at least five servings of fruits and vegetables a day focusing on the antioxidant powerhouses; complex carbs, fatty fish, and a few cups of green tea at least two times a week; a daily handful of nuts; no more than one glass of alcohol per day; and a limited amount of meat and sweets.

Eat more mushrooms during cold and flu season: Research shows that when a virus is present, mushrooms may rally the immune system to fight them.

STEP 6 Catch your zzzzz's 保证睡眠

Get at least seven hours of sleep every night, more if you can.

The first scientists to prove that the body defends itself against disease through the immune system shared the Nobel Prize in 1908.