Lonely people are more likely to strain national productivity and health-care systems from their lack of activity and conduct. Their bodies are distinctly different from the bodies of healthy people. Prolonged loneliness "can put one at risk for chronic health conditions, exacerbate various health conditions, and ultimately put us at increased risk for premature mortality."

Diseases and ailments due to loneliness include the following that lead to poor sleep, poorer cognitive performance, executive control and self-regulation, substance abuse, and suicidal ideation.