Loneliness is associated with elevated levels of the stress hormone cortisol, poor sleep quality, an increased risk for heart disease and stroke, accelerated cognitive decline, heightened systemic inflammation, reduced immune function, anxiety, and depression. Researchers from Brigham Young University put all of this together for a comprehensive study that followed more than 300,000 people for an average of 7.5 years. They learned that the mortality risks associated with loneliness exceed those associated with obesity and physical inactivity and are comparable to those associated with smoking.
