The researchers analyzed data on 2,527 adults (average age, 68), including waist size and body mass index (BMI). To gauge chronic stress, the study relied on analysis of a lock of hair about three-fourths of an inch long, representing about a two-month accumulation of cortisol, a hormone released when a person is stressed. As people’s weight increased, so did their cortisol levels.
Here’s another bad thing about stress: It may be connected to gaining weight – Washington Post