Studies find our hearts can affect how we feel fear
FEAR may be felt in the heart as well as the head, according to a study that has found a link between the cycles of a beating heart and the likelihood of someone taking fright.
Tests on healthy volunteers found that they were more likely to feel a sense of fear at the moment when their hearts are contracting and pumping blood around their bodies, compared with the point when the heartbeat is relaxed.
Scientists say the results suggest that the heart is able to influence how the brain responds to a fearful event, depending on which point it is at in its regular cycle of contraction and relaxation.
Sarah Garfinkel, a researcher at the Brighton and Sussex Medical School, said: "We demonstrate for the first time that the way in which we process fear is different dependent on when we see fearful images in relation to our heart."
The study, to be presented today at the British Neuroscience Association Festival in London, tested the fear response of 20 healthy volunteers as they were shown images of fearful faces while connected to heart monitors.
"Our results show that if we see a fearful face during systole - when the heart is pumping - then we judge this fearful face as more intense than if we see the very same fearful face during diastole - when the heart is relaxed," Dr Garfinkel said.
"From previous research, we know that if we present images very fast then we have trouble detecting them, but if an image is particularly emotional then it can 'pop' out and be seen.
"We demonstrated that fearful faces are better detected at systole, when they are perceived as more fearful, relative to diastole. Thus our hearts can also affect what we see and what we don't see - and guide whether we see fear."
To investigate the phenomenon further the scientists used a brain scanner to show how an almond-shaped region of the brain called the amygdala, which is sometimes called the "seat of emotion", influences how the heart changes a person's perception of fear.
"We have identified an important mechanism by which the heart and brain 'speak' to each other to change our emotions and reduce fear. We hope to explore the therapeutic implications in people with high anxiety," Dr Garfinkel said.
"We hope that by increasing our understanding about how fear is processed and ways that it could be reduced, we may be able to develop more successful treatments for [anxiety disorders], and also for those, such as war veterans, who may be suffering from post-traumatic stress disorder."