cortisol

This shows stem cells

How stress causes gray hair

Study reveals a link between the nervous system and stem cells that regenerate pigment in hair follicles. When stressed, norepinephrine from the sympathetic nervous system causes melanocyte stem cells to activate excessively. The stem cells all convert into pigment-producing cells, prematurely depleting the reservoir. The findings explain the cellular and molecular links between stress and premature hair graying.... Read More...
This shows a cute, but scruffy dog

Dogs mirror owner’s stress

Researchers identify an interspecies correlation between hair cortisol concentrations in humans and dogs during summer and winter months. The cortisol levels were not affected by the amount of activity the dog had during these periods. The study reveals a seasonal effect in higher cortisol levels between humans and animals, and human personality traits significantly affected the dog's level of stress. Findings suggest that dogs often mirror the stress levels of their owners.... Read More...