The Daily Digit is the story behind the numbers that make our world turn. Today we’re looking one of the worst feelings there is: loneliness. A new study by health care provider Cigna has found that 43% of Americans report feeling isolated sometimes or all of the time. To make matters worse, the study found that more than half of Americans feel no one knows them well. Research has shown that loneliness can significantly increase mortality rates — meaning that maintaining close relationships could literally save your life.