Author(s): SHING, C., TAYLOR, J., COOMBES, J., BOND, B., Institution: UNIVERSITY OF QUEENSLAND, Country: AUSTRALIA, Abstract-ID: 1439

INTRODUCTION:
Menopausal transition is characterised by a marked reduction in ovarian hormones and a concomitant decline in cerebrovascular and peripheral vascular function. Exercise is a commonly used non-pharmacological strategy leveraged to improve vascular function. Indeed, studies have shown that in young healthy adults, acute aerobic exercise can acutely improve peripheral vascular function as measured by brachial artery flow mediated dilation (BA-FMD). Emerging evidence supports a dose-response relationship such that greater exposure to shear stress (ie. higher exercise intensity), elicits a greater the improvements in BA-FMD.

Until recently there was no way to confirm if this mechanism existed within the cerebrovascular system. Methodological advancements now allow researchers to directly investigate shear-mediated vasodilation of the internal carotid artery (ICA-FMD) a major conduit artery supplying the brain, using a transient carbon dioxide (CO₂) stimulus. To date, only one study has utilized this technique to demonstrate that following an acute bout of moderate intensity aerobic exercise, shear-mediated ICA-FMD was significantly augmented in young healthy adults. Despite evidence suggesting exercise induced shear can augment both ICA-FMD and FMD, in healthy young adults, it remains unknown if this mechanism is preserved during early-postmenopause in a hypoestrogenic environment.

Study Objective:
This study aims to explore 1) If an acute bout of exercise can augment cerebrovascular endothelial function as measured by ICA-FMD in early postmenopausal women, and 2) Whether this response is influenced by exercise intensity.


METHODS:
Sixteen healthy early postmenopausal women (12 months to 2 years since their last menstrual cycle) will be recruited to participate in a randomized cross-over study. Participants will first be screened for eligibility before undergoing a maximal graded exercise test (GXT) to assess oxygen consumption and set exercise intensity targets. Once completed participants will randomly complete a high intensity interval (8 x ~1 min intervals at 80% peak GXT power) and a moderate intensity interval (4 x ~4 min intervals at 80% of the first ventilatory threshold) exercise session. These exercise bouts will also be work-matched to isolate any independent effect of exercise intensity. During each study visit pre-exercise ICA-FMD and BA-FMD response will be measured followed by a post-exercise measure 40 minutes following the exercise.


RESULTS:

CONCLUSION:
This study aims to advance both the utility of ICA-FMD assessments and address the paucity of literature investigating both the acute effects of exercise and the effect of exercise intensity on vascular function during menopause. We hope these findings will provide mechanistic insight into vascular adaptability during menopause and inform clinicians how to best leverage exercise as a therapeutic intervention during menopause and beyond.