Biopsychological changes after bungee jumping: beta-endorphin immunoreactivity as a mediator of euphoria?

A study on 12 novice bungee jumpers was performed to investigate the influence of acute psychological stress on levels of cortisol in saliva, beta-endorphin immunoreactivity as well as the number of leukocytes in peripheral blood. In addition, heart rate and blood pressure as well as ratings on emotional states were recorded. Furthermore, correlations between ratings on mood and biochemical stress markers were computed. As expected, subjective ratings on anxiety were increased prior to the jump and were markedly reduced after the jump. Salivary cortisol was also increased after the jump and decreased to baseline within the next hour. In contrast, ratings on euphoria increased markedly after performing the jump and remained highly elevated for the next 30 min. An increase of more than 200% in beta-endorphin immunoreactivity after the jump was observed. In contrast to levels of cortisol, the concentration of beta-endorphin recorded immediately after the jump was significantly correlated with ratings on euphoria obtained at subsequent measurements indicating a relationship between beta-endorphins and euphoria. Additional increase of the number of blood leukocytes and of heart rate and blood pressure indicate that various systems of the organism are markedly affected by the exceptional eustress of bungee jumping.