Having high self-esteem doesn’t just feel good, it has physical benefits too. It seems that thinking well of ourselves may protect both the heart and immune system.

High self-esteem makes us feel safer when faced with threats, which in modern western society tend to be related to social status rather than physical danger.

So psychologist Andy Martens from the University of Canterbury in Christchurch, New Zealand, and his colleagues wondered if this protective effect might go further, and dampen our physiological responses as well.

To find out, they carried out a series of experiments involving a total of 184 participants. In one study, participants were given false feedback about their intelligence or personality that was designed to raise or lower their self-esteem. In another, they were asked to rate their natural self-esteem levels each day for two weeks. The team analysed the activity of the participants’ cardiac vagal tone – a measure of how strongly the parasympathetic nervous system (PNS) influences the heart.


Fight or flight

The PNS acts to slow and calm the heart, in opposition to the “fight or flight” state governed by the sympathetic nervous system. The PNS dampens stress and inflammation, and if underactive can lead to cardiovascular problems and autoimmune disease.

In each experiment, higher self-esteem correlated with higher vagal tone. The effect was relatively small, but Martens and his colleagues say this is the first study to show how a change in self-esteem can lead to an immediate change in physiology, and is an important step towards “filling the gap” between self-esteem and health.

Martens suggests that the most reliable way for someone to boost their self-esteem is to surround themselves with supportive friends or family – people who provide convincing positive feedback – rather than, say, trying to think positively.

“Low self-esteem means more than just feeling bad,” he says. “It also means the body isn’t functioning in a very healthy way, and this could have serious health implications down the road.”

Journal reference:Journal of Research in Personality, DOI: 10.1016/j.jrp.2010.07.001