Scientists have long known that prolonged stress can have negative effects on the body, including premature aging, early mortality, chronic disease, depression, and overall poor quality of life. Moreover, stress can also affect the hair, by releasing hormones that change hair pigmentation, turning it gray or white, or cause hair loss. Now, a team of researchers led by the University of Iceland and the National Institute of Public Health of Mexico has found that stress levels are also reflected in how much of the hormone cortisol is...