The Magic Bullet睡觉是灵丹妙药

 

An occasional restless night is nothing to worryabout, but a continuous lack of zzz's can hamper your immune system's abilityto function.

 

 

Though experts often say that sleep requirements vary byindividual, a 2009 Carnegie Mellon study found that anything short of sevenhours nearly triples your odds of catching a cold -- and that means sevenstraight hours, with no middle-of-the-night wake-ups.