Exercise-induced MyoD mRNA expression in young and older human skeletal muscle: A systematic review and meta-analysis

Background: Myoblast determination protein 1 (MyoD) is a master transcription factor that triggers myogenesis and drives muscle growth. Objective: The aim was to assess acute exercise-induced MyoD mRNA expression in skeletal muscle for young and older (age > 50) adults. 

Design: A meta-analysis and systematic review was conducted. 

Methods: A literature search was conducted for studies reporting MyoD mRNA changes in biopsied human muscle taken within 48 h after exercise. Fifty eligible studies with 822 participants (young 20–35 years; older 53–85 years) were included for meta-analysis. 

Results: Significant increases in MyoD mRNA expression in human skeletal muscle were observed 3–12 h post-exercise (standardized mean difference [SMD] = 1.39, p < 0.001), subsiding within 24–48 h (SMD = 0.47, p < 0.001). Older individuals showed a similar time pattern in MyoD mRNA expression post-exercise, but the response is weaker than in younger individuals. Intriguingly, resting levels of MyoD mRNA were higher in older individuals compared to younger individuals in most age-paired studies (SMD = 0.56, p < 0.01). Considering the decline in anabolic hormones during later life, this systematic review highlights age- and sex-related impacts on exercise-induced MyoD mRNA expression in human skeletal muscle, emphasizing the roles of sex hormones and insulin. 

Conclusion: Pooled results from the eligible studies suggest a blunted exercise-induced increase in MyoD mRNA in skeletal muscle after age 50, likely due to elevated basal MyoD expression as a compensatory mechanism against persistent catabolic conditions in aging muscle. Protocol

Registration: Registration number: CRD42023471840 (PROSPERO). Copyright © 2025 The Author(s), under exclusive licence to Springer Nature Switzerland AG.