The acute effect of a laboratory shame induction protocol on endothelial function in young, healthy adults.

The objective of this study was to examine the impact of a shame induction protocol on endothelial function. Fifteen participants (n = 7 men, n = 8 women) completed both a written shame induction protocol and a control protocol on two different experimental days. Pre- and post-protocol we assessed: (1) endothelial function and arterial shear rate via a standard brachial artery reactive hyperaemia flow-mediated dilatation (FMD) test across two post-intervention time points (15 and 35 min post); (2) perceived shame via the experiential shame scale (ESS); and (3) cortisol and soluble tumor necrosis factor alpha receptor (sTNFαRII) through oral fluid analysis. Shame increased after the shame induction protocol (pre, 2.9 ± 0.6 vs. post, 3.7 ± 0.5, P < 0.001) but not the control protocol (pre, 3.0 ± 0.5 vs. post, 2.8 ± 0.5, P = 0.15; protocol by time interaction, P < 0.001). When all three time points were included in the analysis, %FMD did not change over time. Considering only the lowest post time point, %FMD decreased significantly in response to the shame protocol (pre, 4.8 ± 1.9 vs. post, 3.2 ± 1.6, P < 0.001) but not the control protocol (pre, 4.2 ± 1.8 vs. post, 3.8 ± 1.5, P = 0.45; protocol by time interaction, P = 0.035). Covariation of the shear rate stimulus for FMD did not alter the FMD results. When including both the control and shame protocols, but not the shame protocol alone, increased shame was significantly associated with decreased FMD (r = -0.37, P < 0.046). There were no significant time by protocol interaction effects for cortisol or sTNFαRII. In conclusion, temporary increases in shame might cause transient endothelial dysfunction which, if chronically repeated, could manifest as reduced vasoprotection against atherosclerosis.