Under normal circumstances (hot days, at the gym), perspiration is meant to cool you down. Sweat is produced and then evaporates, carrying heat away from your body. All sweat feeds bacteria on your skin, which digest the stuff and produce B.O. But when you’re stressed, the odor is stronger and more pungent. Adrenaline and cortisol rush into your bloodstream, turning on other glands called apocrine glands that produce a fatty, protein-packed sweat that bacteria feast on. What follows is the particularly stinky stink of panic.