On a biological level, loneliness puts us in a stress state, and in the short-term, that stress can be good. It can motivate us to go and seek out other friends and family members and to hopefully feel more connected. But we run into problems when that loneliness is prolonged and when the stress state that it causes is prolonged as well. We know that chronic stress is associated with higher levels of inflammation in the body, which can lead to an increased incidence of heart disease and other chronic illnesses.