Unfair and unreasonable bosses can increase their employees' blood pressure and raise the risk of a heart attack or stroke, British doctors say.

A study by researchers at Buckinghamshire Chilterns University College in England found that blood pressure of healthcare assistants was higher when they were supervised by someone they considered unreasonable, according to a Reuters news report.

"An unfavorably perceived supervisor is a potent workplace stressor," Dr. Nadia Wager said in the report.