Author(s): WANG, C.W.1, FANG, S.H.1, WANG, S.C.2, HE, C.S.2, Institution: NATIONAL CHUNG CHENG UNIVERSITY, Country: TAIWAN, Abstract-ID: 664

INTRODUCTION:
Previous research has shown that high-intensity resistance exercise has been associated with adverse effects on cardiovascular function, including rapid elevation of blood pressure and unfavorable release of cardiac markers [1]. The secretion of female hormones varies across different menstrual phases, with estrogen known to inhibit the activity of the sympathetic nervous system (SNS) and induce the release of nitric oxide (NO), promoting vasodilation [2]. Moreover, dark chocolate, rich in cocoa flavanols, contributes to mechanisms preventing cardiovascular disease, including improvements in vascular endothelial function and reductions in blood pressure [3, 4]. This study aims to investigate whether adverse cardiovascular effects induced by high-intensity resistance exercise can be mitigated through estrogen secretion and dark chocolate supplementation.
METHODS:
Thirty-one healthy adult women (with regular menstrual cycles) were recruited as participants. During a consecutive two-month period, conducting a total of four experiments (Early Follicular-DC, Early Follicular-MC, Mid Luteal- DC and Mid Luteal- MC). On the day of the experiment, resting values (Rest) of finger-toe pulse wave velocity (ftPWV), blood pressure, Arterial Velocity Pulse Index (AVI), and Arterial Pressure Volume Index (API) were collected. Participants were then provided with a standard breakfast along with either 85% dark chocolate or milk chocolate (1 g/kg). After a 2-hour rest period following breakfast, baseline measurements after supplementation (baseline-C) were taken. Subsequently, participants engaged in warm-up exercises followed by a single high-intensity resistance exercise session (5 sets of 6 repetitions) at 75% of 1RM, which included squats, bench presses, and deadlifts. Measurements were also taken immediately post-exercise (T0) and 1 hour post-exercise (T60). The data were analyzed using two-way repeated measures analysis of variance (ANOVA).
RESULTS:
The Early Follicular-MC group exhibited significantly higher values in ftPWV and API at both baseline-C and T0 compared to the Mid Luteal-DC, Mid Luteal-MC, and Early Follicular-DC groups (p < .05). Moreover, the Early Follicular-MC and Early Follicular-DC groups demonstrated significantly elevated SBP and API at rest compared to the Mid Luteal-MC and Mid Luteal-DC groups (p < .05). Additionally, the Early Follicular-MC group exhibited significantly higher SBP at baseline-C compared to the Mid Luteal-DC group (p < .05). However, no significant differences were observed in DBP and AVI among the groups.
CONCLUSION:
The findings of the study indicate that women demonstrate significantly lower SBP and arterial stiffness during the mid-luteal phase in comparison to the early follicular phase. Additionally, the consumption of dark chocolate leads to a notable reduction in blood pressure and arterial stiffness. Furthermore,it serves to attenuate the swift elevation in blood pressure and arterial stiffness induced by high-intensity resistance exercise.