NOW we know why ZZ TOP is still alive and kickin'. A new study out of the University of Southern Queensland in Australia has found that a big secret to being healthy is . . . a BIG, SEXY BEARD. Here's why . . .

#1) Beards protect your face from the sun. Men with beards . . . or bearded ladies in carnivals . . . are exposed to 30% fewer UV rays on their faces.

#2) Beards can trap allergens that might cause asthma attacks.

#3) They keep water from leaving your skin, which keeps it moisturized . . . and makes a person's face AGE more slowly.

#4) They raise your neck temperature, which helps fight colds. (Daily Mail)