PhD students participating in August Krogh seminars receive 0,2 ECTS per seminar
AKC Double Seminar: Sex Hormones in Human Physiology: Roles Beyond Reproduction
August Krogh Double Seminar
Maureen MacDonald
Professor of Kinesiology and Dean of Science, McMaster University, Canada.
Breaking down barriers to inclusion of women in vascular exercise physiology research
Abstract
One commonly cited barrier to inclusion of females in vascular exercise physiology research is the perception that sex differences and sex hormones have a significant impact on vascular structure and function. Much of this perception or sex and sex hormone differences is based on early research that indicated sex and menstrual cycle phase differences in brachial artery flow mediated dilation and other common measures of vascular function. The purpose of this talk will be to outline the research we have conducted in my lab to address this perceived barrier to inclusion and to propose a framework to facilitate more inclusion of females in our research in the future.
I will highlight the contributions my lab has made to characterizing the state of the literature through systematic reviews and meta-analyses. In these reviews we identified that the proportions of female participants in vascular exercise physiology research has remained low and constant for the last 20 years. We also observed that while there is relatively consistent evidence of differences in vascular structure and function between young healthy males and females, the differences across the menstrual and hormonal contraceptive cycles in females are small with lower certainties of evidence. We have suggested that this lower certainty of evidence can be addressed with careful consideration of methodology in terms of both the hormonal cycle and vascular function assessments.
I will describe the outcomes of some comprehensive integrative physiology studies we have conducted in young healthy women and the companion endothelial cell serum exposure studies. Finally, I will outline some studies we are currently conducting to examine the vascular responses to different exogenous progestins found in hormonal contraceptives and a framework we have developed to improve rigor and reproducibility in cardiovascular research with female participants.
Research Profile
Maureen J MacDonald is a full professor in the Department of Kinesiology and the Dean of Science at McMaster University. As director of the Vascular Dynamics Laboratory, she conducts research in exercise physiology with specialization in the application of ultrasound techniques to the assessment of the peripheral blood vessels. Dr. MacDonald is a member of the Canadian Society for Exercise Physiology, the American College of Sports Medicine, the American Physiological Society, and the European College of Sports Science. She is currently a Global Chair at Manchester Metropolitan University and a Visiting Professor at Loughborough University in the UK.
Literature
Stuart Phillips
Professor and Canada Research Chair, McMaster University, Canada
Female Hormonal Cycle Syncing for Exercise Performance and Muscle Adaptation: Sorting Fact From Fiction
Abstract
The hypothesis that female hormonal fluctuations across the menstrual cycle (MC) and phases of oral contraceptive pill (OCP) use substantially modulate exercise performance and muscle adaptation has driven widespread but conflicting research. The aim of my talk, is to critically examine proposed mechanisms—ranging from systemic estrogen (E2) and progesterone (P4) receptor signaling to satellite cell activation and muscle protein turnover—and synthesize human evidence across multiple domains.
I will review endocrine–substrate interplay, summarizing a comprehensive meta-analysis showing no meaningful differences in resting or exercise-induced substrate oxidation (RER, carbohydrate vs. fat use) between follicular and luteal phases or between active and placebo OCP phases. Next, I will analyze exercise capacity studies, highlighting trivial MC-phase effects on endurance or strength outcomes, the methodological pitfalls in phase verification, and the role of menstrual symptoms—rather than hormones per se—in perceived performance.
Central to muscle adaptation, I will explore mechanistic data on E2– and P4–mediated regulation of satellite cell activation via ERα/β and downstream myogenic transcription factors, contrasting robust rodent ovariectomy models with limited and inconclusive human data. We present gold-standard stable isotope studies demonstrating identical integrated muscle protein synthesis (MPS) and myofibrillar proteolysis (MPB) responses to resistance exercise in mid-follicular vs. mid-luteal phases, and in active vs. inactive OCP phases. Finally, I’ll address chronic resistance training interventions purported to exploit “anabolic” follicular windows, revealing inconsistent hypertrophy and strength benefits and questioning the practicality of phase-based periodization.
By dissecting hormone–muscle mechanisms, scrutinizing substrate and performance outcomes, and evaluating protein turnover and training adaptations, this talk will distinguish established facts from prevailing myths. Attendees will gain clarity on whether syncing exercise to hormonal cycles yields meaningful advantages—or whether consistent, symptom-guided training remains the most evidence-based approach for female athletes and exercisers.
Research Profile
Dr. Stuart Phillips is a Distinguished University Professor in the Department of Kinesiology and a member of the School of Medicine at McMaster University. He is a Tier 1 Canada Research Chair in Skeletal Muscle Health. Dr. Phillips' work centers on the interaction of exercise/physical activity, aging, and nutrition in skeletal muscle and body composition. Dr. Phillips is a fellow of the American College of Sports Medicine (ACSM) and the Canadian Academy of Health Sciences (CAHS). He has been in the top 1% of cross-field (nutrition and physiology) highly-cited scholars globally for six straight years, 2018-2023.
Literature
Menstrual cycle phase does not influence muscle protein synthesis in healthy young women
Time
27 June 2025
14:00-15:30 CET (snacks and drinks will be served after the seminar)
Venue
Auditorium 1, August Krogh Building, Universitetsparken 13, DK-2100 Copenhagen
Registration
Participation is free, but please register here.
For PhD students
PhD students participating in August Krogh seminars receive 0,2 ECTS per seminar
Contact
Kate Aiko Wickham, kawi@nexs.ku.dk
