Most people know what it’s like to be lonely. Many of us have encountered life experiences that have left us yearning for more human interaction. Whether it’s the death of a loved one, moving to a new city, or simply spending a weekend indoors, the truth is that loneliness feels terrible. After all, it makes sense that the human brain has evolvedto become dependent on social interactions. Humans have an inherent desire to be with other people and feelings of loneliness or isolation has several detrimental effects on a person’s well-being.

Loneliness is a surprising epidemic that affects millions of people. Studies have shown that about one-fifth of Americans report feelings of loneliness. It’s something that affects people of every race, age, and gender, though senior citizens seem to have it the worst.

The loneliness epidemic is much worse than one might initially think. It might be tempting to say that loneliness is nothing more than a feeling, but researchers have found that it can be deadlier than obesity. (To be specific, lonely people have a 50% greater mortality rate than non-lonely people whereas obese people have an 18% greater mortality rate than non-obese people.)

One study from Jama International Medicine observed the lifestyles and habits of about 45,000 people over a four year period. All participants either had heart disease or were at risk for it. During the follow up period, researchers recorded 4338 deaths and 2612 cardiovascular deaths. In both cases, lonely people were slightly more likely to die than non-lonely people.

In a follow-up study, researchers looked at how loneliness affects people age 60 and up over a six year period. They found that loneliness has several adverse effects on the elderly population. First of all, seniors who reported loneliness also reported high levels of functional decline. Functional decline was measured using four different factors: ability to perform daily activities such as dressing and bathing, ability to perform upper extremity tasks, ability to walk, and ability to climb stairs. Lonely seniors reported increased difficulty in all four of these areas.

A comparative analysis of lonely and non-lonely seniors found that the lonely seniors also suffered from various medical conditions at a higher rate such as hypertension (3.1% difference), diabetes (2.4% difference), and heart conditions (5.3% difference). Not surprisingly, isolated seniors were also 27.6% more likely to suffer from depression and 8.6% more likely to die during the study period.

A study from the University of Chicago also found that loneliness can significantly affect someone’s blood pressure, particularly when they are older. Blood pressure differences between lonely and non-lonely people are less significant among people in their fifties, but the gap grows with age. In fact, loneliness can increase someone’s blood pressure by up to 30 points. Researcher Louise Hawkley noted that exercise and weight loss help reduce blood pressure by the same amount that loneliness increases it. In other words, a lonely person who exercises and diets is likely to have to same blood pressure as a non-lonely person who does neither of those things.

Another major reason loneliness can be deadly is the way that it affects your immune system. A study from psychologist Steve Cole and professionals from UCLA School of Medicine, University of California at Davis, and University of Chicago found something rather alarming. Loneliness causes abnormalities in the body’s monocytes, a white blood cell that helps defend the body against infection. Social isolation causes the monocytes to stay immature. Rather than helping the body fight infection, immature monocytes instead decrease immunization.

John Cacioppo, a professor of psychology at the University of Chicago, has been studying this subject in-depth for years. He says that part of the reason loneliness can be so deadly is because it creates a feedback loop that reinforces negative thoughts and feelings. Cacioppo recommends that elderly people can get out of this vicious cycle by staying in touch with friends and family and by attending family gatherings.

Senior man photo available from Shutterstock