Evidence regarding the impact of menstrual phase on endothelial function is conflicting, and studies to date have examined responses only over a single cycle.It is unknown whether the observed inter-individual variability of phase changes in endothelial function reflects stable, inter-individual differences in responses to oestrogen (E 2 ; a primary female sex hormone). The purpose of this study was to examine changes in endothelial function from the early follicular (EF; low-E 2 ) phase to the late follicular (LF; high-E 2 ) phase over two consecutive cycles. Fourteen healthy, regularly menstruating women [22 ± 3 years of age (mean ± SD)] participated in four visits (EF Visit 1 , LF Visit 2 , EF Visit 3 and LF Visit 4 ) over two cycles. Ovulation testing was used to determine the time between the LF visit and ovulation. During each visit, endothelial function [brachial artery flow-mediated dilatation (FMD)], E 2 and progesterone were assessed. At the group level, there was no impact of phase or cycle on FMD (P = 0.48 and P = 0.65, respectively). The phase change in FMD in cycle 1 did not predict the phase change in cycle 2 (r = 0.03, P = 0.92). Using threshold-based classification (2 × typical error threshold), four of 14 participants (29%) exhibited directionally consistent phase changes in FMD across cycles. Oestrogen was not correlated between cycles, and this might have contributed to variability in the FMD response. The intra-individual variability in follicular fluctuation in FMD between menstrual cycles challenges the utility of interpreting individual responses to phase over a single menstrual cycle.

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.

Passive leg movement-elicited hyperaemia (PLM-H) provides an index of lower-limb microvascular function. However, there is currently limited information regarding the reliability of PLM-H and no reliability information specific to women. The purpose of this study was to determine the reliability of PLM-H in women on two separate days. Seventeen young, healthy women [22 ± 3 years old (mean ± SD)] participated in two identical visits including three trials of PLM. Using duplex ultrasound, PLM-H was characterized by six indices: peak leg blood flow (LBF) and vascular conductance (LVC), peak change above baseline (Δpeak) for LBF and LVC, and area under the curve above baseline (AUC) during the first 60 s of PLM for LBF and LVC. The results demonstrated good day-to-day reliability of PLM-H characterized as peak LBF [r = 0.84, P < 0.001; intraclass correlation coefficient (ICC) = 0.84; coefficient of variation (CV) = 13.2%],