It’s a sad but simple truth - loneliness kills. Here’s how feeling socially isolated changes your body and your brain: 

  • First: Loneliness confuses the immune system. Psychiatrist Dr. Steve Cole says that the immune systems of lonely individuals tend to ignore viruses, and overreact to bacteria. Eventually, that out-of-balance response increases their risk of heart problems, cancer, and Alzheimer’s disease. 

  • Next: Loneliness raises levels of the stress hormone cortisol. When that happens, blood pressure can reach dangerous levels. 

  • The 3rd way loneliness hurts your health: It alters sleeping patterns. Dr. John Cacioppo is psychologist and an expert on social isolation. And he says that lonely people wake more often at night. So, they don’t get the type of rest that restores the brain and allows the body to make repairs. 

  • And finally: Loneliness changes how you think. According to the Journal of Cognitive Neuroscience, isolated people have less activity in a part of the brain that judges risk and enjoys rewards, which means, lonely people enjoy social interaction less than non-lonely people. They also tend to judge other people harshly. Which means they’re less likely to make friends.

Now, if you just moved to a new city or started a new job and you feel lonely, don’t panic. A study in the journal Personality and Social Psychology Review found that regular contact with other people can undo much of the damage caused by loneliness. But, you don’t want to wait too long to start making friends. The same study found that people who’ve been isolated for more than 6 months often need training to increase their social skills and change their defensive outlook.