Dr Danielle Hiam1, Ms Annabel Critchlow1, Dr Steve O'Bryan2, Professor Séverine Lamon1
11Institute for Physical Activity and Nutrition (IPAN), School of Exercise and Nutrition Sciences, Deakin University, Geelong, Australia, 2Institute for Health and Sport, Victoria University, Melbourne, Australia
Biography:
Dr Hiam is a early career postdoctoral fellow at Deakin University. Her expertise spans skeletal muscle physiology, epigenetics, endocrinology, and bioinformatics. Her research focuses on uncovering sex-specific mechanisms underlying muscle adaptation in health and disease, with the broader goal of improving the representation of females in fundamental basic research.
Abstract:
Introduction:
The menopausal transition is marked by a decline in circulating estradiol (E2) and is associated with deterioration of muscle mass and function. However, the direct impact of this hormonal shift on skeletal muscle composition and function remains poorly understood.
Aim:
To comprehensively phenotype skeletal muscle in females aged 18-80 years to determine how physiological, functional, and molecular characteristics relate to age-related changes in circulating sex hormones.
Method:
A cross-sectional cohort of 96 females were recruited. Participants underwent body composition analysis, neuromuscular function and strength testing, muscle biopsy for transcriptome sequencing and blood sampling to assess the sex hormone profile.
Results:
Although age was linearly associated with declines in muscle torque, velocity, and power, we observed an accelerated reduction in neuromuscular function coinciding with the menopausal transition. Mediation analysis revealed a significant indirect effect of E2 on muscle torque and peak power through neural drive, indicating that neural drive partially mediates the relationship between E2 and force generation.
Conclusion:
Muscle strength and power may be less directly affected by E2 declines post-menopause, while neural input may be more sensitive to hormonal changes. This suggests hormonal shifts may precede or amplify neural alterations even when muscle mass remains relatively preserved.