We have all felt shivers on some occasion; that tingling that runs through our body, causing goosebumps and making us shake. But what causes this reaction of the organism? What science says about it?

According to Hugo Sanchez Castillo, professor at the Faculty of Psychology of the National Autonomous University of Mexico (UNAM), shivers are generally a reaction regulated by the autonomic nervous system and are related to stress.

Basically, when we perceive an event as dangerous, a series of reactions associated with it appear, causing mobilization of energy to produce an explosive effect, said the academic. For example, blood pumps to the arms and legs, secretion activity of stomach movements decrease, adrenaline is released, and dopamine increases; all this gets us ready for a fight or flight situation.

Within all this paraphernalia shivers appear, a common reaction to stress, or distress. Therefore, it is very difficult to put it into a pathological context; and it is often misunderstood.

Generally speaking, it is a response of the body, and manifests as a kind of tingling that runs through the body and skin. We have a number of receptors that react to vibration, causing mobilization of energy, and muscle contractions and general piloerection.

This feeling can occur if the stimulus is positive or negative; for example, when we see a person who is appealing to us, when we present an exam or when we are in a highly stressful situation in a dark alley.

Some studies have tried to determine the relevance of shivers, because it is not a primary defense reaction. However, it seems that it is an important component that prepares the body for a global response, either fight or flight, Sanchez Castillo said.