Constant negativity and cynicism could put you at higher risk of heart disease, according to a recent study.
A team of US researchers explored three kinds of hostility - emotional, behavioural and cognitive. They found cognitive, cynical hostility to be the most harmful.
Lead author Alexandra Tyra says cynicism can have short and long term health effects.
"These findings reveal that a greater tendency to engage in cynical hostility can be harmful not only for our short-term stress responses but also our long-term health."
The researchers conducted 20 minute stress tests on 196 participants. Participants were given five minutes to come up with a five minute speech to defend themselves against a suspected crime - either a traffic violation or shoplifting.
They then had to perform a five minute maths test while their heart and blood pressure were measured every two minutes.
All participants were tested during two lab sessions approximately seven weeks apart.
In most people, stress activates a fight or flight response, but if the same event happens again, this response is dulled., However, highly skeptical people never experience this dulling, and will feel the same level of stress over and over again.
This repeated stress places increased strain on the cardiovascular system.
Tyra says future research would be useful to examine the implications of cynical hostility across the lifespan, "perhaps following individuals as they grow older to see whether a greater tendency to use cynical hostility while young is actually related to poor cardiovascular outcomes at an older age, such as a heart attack."
However she says the research is also useful now.
"Perhaps the next time someone thinks a negative thought about the motives, intentions or trustworthiness of a friend, co-worker or politician, they'll think twice about actively engaging in that thought."