Bungee jumping may give pleasure, but may also affect the immune system. A new study shows that innate immune response is suppressed following bungee jumping. Stress has been known to be a known risk factor for infection and autoimmunity (Autoimmunity is a condition in which one's immune system recognizes own tissues as foreign and mount an immune response- examples: type I diabetes, myasthenia gravis).
Stress presumably interacts with immunity due to the release of stress hormones such as catecholamines and cortisol. The authors used bungee jumping, a novel human model of acute stress, to test whether acute stress induced release of stress hormones and cause an immune suppressive phenotype.
The study was published in the scholarly journal Molecular Medicine by Tom van der Poll and colleagues at the University of Amsterdam, The Netherlands. According to the authors high-altitude jumping seems almost universally to be associated with substantial induction of flight/fright responses. This was supported by recent studies that showed increased fear, dizziness and body sway in all participants during height exposure, indicating that exposure to substantial heights induces a universal stress response.
The authors subjected male healthy volunteers, who never before bungee jumped, to a bungee jump from an altitude of sixty meters. Twenty volunteers were included in the study; half of this group was pre-treated for three days with the beta receptor blocking agent propranolol. Beta receptors are targets of catecholamines- fight-or-flight hormones released by adrenal glands. Blood was drawn 2 hours before, right before, immediately after and 2 hours after the jump. They found that pre-treatment of volunteers with propranolol abolished the effects of jumping on coagulation and endothelial activation but left the inhibitory effects on innate immune function intact.
The authors suggest that their results may have importance for linking stress to the risk of infection as well as autoimmunity. However, when they say "stress in humans is associated with higher vulnerability to infection as well as the development of autoimmune disorders like allergy or inflammatory bowel disease", categorizing allergy as an autoimmune disorder might not have been appropriate.
In this interesting study, the authors concluded that bungee jumping leads to a catecholamine independent immune suppressive phenotype.
Source: David J. van Westerloo1, Goda Choi, Ester C. Lowenberg, Jasper Truijen, Alex F. de Vos, Erik Endert, Joost C.M. Meijers, Lu Zhou, Manuel P.F.L. Pereira, Karla C.S. Queiroz, Sander H. Diks, Marcel Levi, Maikel P. Peppelenbosch and Tom van der Poll .
Acute stress elicited by bungee jumping suppresses human innate immunity. Molecular Medicine Dec 2010 (pre-print). Pubmed Citation.