We all know that hanging around complainers causes people to catch their negativity. Bitching, moaning, and general drama are contagious. But that's apparently not the only problems you can catch if you spend too much time with the eternally pessimistic -- you might also pick up a host of health problems too.

Negativity has been conclusively shown to rewire your brain, making it easier to see the bad in the world and harder to see the good. (The opposite is also true -- positivity is a muscle that grows with use.) But science is just as certain that negative feelings like anger, hostility, and cynicism are also terrible for you body.

Negativity can kill you...

Take anger, for example. Being with people who tick you off wastes precious mental energy, but it can also take a toll "on the body in the form of high blood pressure, stress, anxiety, headaches and poor circulation. Research also shows that even one five-minute episode of anger is so stressful that it can impair your immune system for more than six hours. All of these health issues can lead to more serious problems such as heart attacks and stroke," explains cardiologist Dr. Cynthia Thaik.

Distrust is also harmful. "A 2014 study published in the journal Neurology linked high levels of cynicism later in life... to a greater risk of dementia compared to those who were more trusting," reports Health. "A 2009 study from the journal Circulation looked at data from nearly 100,000 women and found that the most cynical participants were more likely to have heart disease than the least cynical folks."

One giant study of Chinese Americans even found that those who believed in Chinese astrology and whose birthdays were considered "inauspicious" actually died earlier than non-Chinese and non-believing Chinese Americans born at the same time, taking in account lifestyle factors and other variables. It's not because there's anything to astrology. It's because negativity and pessimism can quite literally hasten your death.

... and negativity is catching.

All of which is completely terrifying. But it's even scarier if you consider just how contagious these feelings can be.

"The more time you spend with [negative people] around you, the more you will become like them. Psychologist Elaine Hatfield has done the research. She has found out that we start to imitate facial expressions, posture and even tone of voice of those we spend a lot of time with. Most importantly, we adopt their mental state as well. Since we're empathetic people, we feel with them. If they're in a bad mood, so will we be," reports John Stanley Hunter on Business Insider.

The only reasonable conclusion to reach from all this science is that it's past time to ditch the most negative people in your life. Or if you're pretty much stuck with some of them, take measures to neutralize their negativity and learn to channel your own anger in a more healthful way. Finally, if you have to complain together, opt for the only kind of complaining that's actually good for you.