So this is the time of year when you really want it to be in top-notch condition. Here's what it takes to make that happen.
Let's start with a snooze. Sleep is key to keeping your immune system strong.
Dr. Neal Chaisson, a pulmonologist Cleveland Clinic says don't skimp on your sleep.
"Getting the proper amount of sleep actually helps you to make sure your body's immune system is optimized," he said. "Your body's muscles, your brain is optimized and many times the fruits of good sleep hygiene are far better than just you won't get sick. People tend to operate more efficiently and people tend to be more attentive."
The vitamins and minerals provided by a diet high in fruits and vegetables will also help your immune system to run at full-strength.
Studies have shown vitamins A, B6, and D all play a role in helping the body fight certain diseases and infections.
Exercising also helps to build your immune system by improving circulation and increasing the amount of white blood cells in the body.
The job of the white blood cells is to fight disease.
But to keep your immune system functioning properly, Chaisson says it is critical that you do not smoke because the toxins in cigarette smoke, damage infection-fighting cells.
"We know for a fact, after many years of research that smoking is associated with a higher risk for infections and it is preventable, in my opinion," Chaisson said.
Chaisson also says health store products claiming to boost your immune system probably don't.
He says to save your money until there is more research behind the claims.