In her book about Yoga, Shakta Kaur Khalsa sites a study done at the American Public Health Institute in which they found that “middle-aged people who give up hope are at a greater risk of dying of heart disease.” 

The study followed the subjects’ attitudes toward life, and used ultrasound scans on their arteries.  Four years and 942 people later, the conclusion was that giving up hope has the same effect on the arteries of a middle-aged person as smoking 20 cigarettes a day.

So, maintaining hope is an essential quality of health and survival, and yet there are so many of us without it.  Hope is a funny thing.  It is like faith in that it requires absolute belief in something that you cannot see or prove.