Chronic stress also wreaks havoc on your brain. Cortisol, the so-called "stress hormone," can actually reduce your brain's ability to access short-term memories. A 1998 study in the journal Nature found that half an hour after being stressed by an electric shock, rats forgot how to navigate a maze. A 2012 study in Biological Psychiatry showed that people who experience "cumulative adversity"—that is, repeated bad events over the long term—have less gray matter in the prefrontal cortex, which is responsible for self-control, emotions, and even insulin regulation.

Plus, stress is just not sexy. All the stress hormones a body produces come at the expense of all-important sex hormones, like testosterone, estrogen, and those responsible for sperm production and ovulation. In women, that, plus the mental anguish of chronic stress, can lead to a drastic drop in their sex drive. For men, stress has effects on the blood vessels that can cause erectile dysfunction. But stress also does men another disservice: according to a 2012 study in the journal Nature Communications, men with a lower cortisol level were judged as more attractive by women. One more reason to take some "me" time. Looking for more reasons to take deep breaths during that Thanksgiving dinner? Watch the videos below.