To some extent we do know. We know people who are lonely tend to be less active, and we know people who are less active tend to have worse health. On the Greek

To some extent we do know. We know people who are lonely tend to be less active, and we know people who are less active tend to have worse health. On the Greek island of Ikaria for example[1], we know that people regularly live to be 90 years old and that even at that age they remain incredibly social and physically active. [1] http://www.bbc.com/travel/story/20171116-the-greek-island-with-the-key-to-longevity http://www.bbc.com/travel/story/20171116-the-greek-island-wi...