When you eat too much junk food, your blood sugar rises rapidly, then crashes - causing your body to release stress hormones that impair your ability to stay well. Eat more whole grains, fruits and vegetables instead.
Working out for 30 minutes a day boosts immune cell production and lowers stress hormones. But heavy exercise (like hitting the gym for two hours) has the opposite effect. Aim for three to four short workouts weekly.
Wash your hands correctly
Viruses and bacteria can linger on pens, phones and doorknobs. Scrub your hands with a soap and water for 20 seconds (as long as it takes to hum the song "Happy Birthday To You" twice) before eating and after using the bathroom.
Watch your bag
One of the sneakiest sources of germs is your purse: Drop it on the floor and viruses stick. Carry a leather or vinyl one, and wipe it down when you get home (regular leather cleaner will work).