Researchers have found that loneliness disrupts the fight-or-fight response. This leads to a decrease in protecting white blood cells, lower antiviral responses and increased inflammation, and are at greater risk for chronic pain, chronic illness and infection. A study of 3,012 adults who were 45 years of age and older conducted by AARP found that 55 percent of the respondents who reported being in poor health were lonely, compared to 25 percent of respondents who reported being in very good to excellent health.