For most people, cortisol, the vital hormone that controls stress, increases when they wake up. It's the body's way of preparing us for the day.

But in police officers who've experienced intense stress on the job, cortisol functions much differently, according to recent research from the University at Buffalo and funded by the National Institute for Occupational Safety and Health (NIOSH).

A study of more than 300 members of the Buffalo Police Department suggests that police events or conditions considered highly stressful by the officers may be associated with disturbances of the normal awakening cortisol pattern. That can leave the officers vulnerable to disease, particularly cardiovascular disease, which already affects a large number of officers, reports Medical Xpress .

"We wanted to look at what stressors most affect police officers in their work and what affect that has in the dysregulation of this awakening cortisol pattern," said John Violanti, PhD, research professor of epidemiology and environmental health in UB's School of Public Health and Health Professions.

"Past studies haven't really looked at the intensity of the stressor and how it affected this cortisol pattern. Here we looked at actual intensity," adds Violanti, lead author on the paper, published in the January issue of the journal Psychoneuroendocrinology.

The study included 338 Buffalo officers who were enrolled in the Buffalo Cardio-Metabolic Occupational Police Stress (BCOPS) study, a long-term study Violanti began in 1999.