Loneliness: 5 things you may not know

BERLIN, GERMANY - DECEMBER 15: Three persons with umbrella walk along the river Spree on December 15, 2017 in Berlin, Germany. (Photo by Florian Gaertner/Photothek via Getty Images)

Story highlights

  • For some, chronic loneliness is a way of life
  • Loneliness can hurt your ability to sleep well
  • It may also contribute to dementia and heart problems, studies suggest

Dhani Jones is a former professional American football player, entrepreneur and author of "The Sportsman: Unexpected Lessons From an Around-the-World Sports Odyssey." He's shared his best advice with CNN for a new Digital Studios series called "Be a Champion." This article was originally published in 2014.

(CNN)Nearly everyone feels lonely at some point. The good news is, for many of us, it's a temporary condition, perhaps one caused by a life change: moving to a new location, for instance, or starting a new job.

But for other people, loneliness is a way of life, one that may stem not from the number of people around them but from a lack of connection with others. And, research has showed, chronic loneliness can have adverse consequences for your health.
    Scientists are still examining the link between mental and physical health and how loneliness affects our bodies. But you may not know about some of their findings over the years.

      It may affect your brain in a way similar to physical pain

      As CNN's Dr. Sanjay Gupta writes in a column for O Magazine regarding a 2003 study:
      "A remarkable study led by Naomi Eisenberger, an associate professor of social psychology at UCLA, found that being excluded -- which can push you to the social perimeter and, as a result, cause feelings of loneliness -- triggered activity in some of the same regions of the brain that register physical pain.
        "From an evolutionary perspective, this makes sense; our prehistoric ancestors relied on social groups not just for companionship, but for survival. Staying close to the tribe brought access to shelter, food, and protection. Separation from the group, on the other hand, meant danger.
        "Today when we feel left out, our bodies may sense a threat to survival, and some of the same pain signals that would engage if we were in real physical danger are flipped on. In the chronically lonely, levels of the stress hormone cortisol shoot up higher in the morning than in more socially connected people and never fully subside at night."

        It can keep you from getting a good night's sleep

        People who feel lonely tend to experience more nighttime sleep disruptions than those who don't, a small 2011 study found.
        Researchers found that the link between sleep disruptions and loneliness persisted even after marital status and family size were taken into account, suggesting that loneliness depends on how people perceive their social situation rather than the situation itself.
        The 95 participants in the study all had strong social connections and were part of a close-knit, rural South Dakota community. Yet, researchers found, even small differences in their degrees of loneliness were reflected in their sleep.

        It can increase your risk for dementia

        In a 2012 study of nearly 2,200 older adults living in Amsterdam, researchers found that participants who reported feeling lonely -- regardless of the number of friends and family surrounding them -- were more like