Human skeletal muscle possesses an epigenetic memory of high intensity interval training affecting mitochondrial function

An exposure to hypertrophic stimuli has been shown to lead to faster and larger growth of skeletal muscle when subsequently repeated. Aside from acquired myonuclei permanence, epigenetic modification appears to be involved in the hypertrophic memory at skeletal muscle level. Endurance training interventions increase mitochondrial content and induce mitochondria biogenesis. We aimed to explore whether repeated endurance stimuli can induce changes in mitochondrial function and dynamics due to epigenetic memory. We hypothesized mitochondrial adaptations in response to high-intensity interval training might be influenced by muscle memory at epigenetic level. METHODS: Sixteen subjects (25±5years) underwent to two repeated aerobic training periods (training and retraining) separated by 12 weeks where they were invited to return to their habitual life (detraining). Each training lasted 8 weeks and consisted of a combination between high-intensity interval and sprint interval cycling exercises. At baseline and after training, detraining and retraining peak oxygen consumption (V̇O2peak) and peak power output (Wpeak) were measured. Vastus lateralis muscle samples were collected and mitochondrial respiration (O2 flux by high-resolution respirometry), mitochondrial dynamics, DNA methylation, and gene expression analysis were performed. RESULTS: V̇O2peak and Wpeak improved during both training and retraining (all p0.58). Mitochondrial respiration improved in both training and retraining (both p2 flux changes observed after retraining were greater than those after training (p Simone Porcelli was supported by a grant from Sports Medicine Italian Federation (FMSI01092021). This is the full abstract presented at the American Physiology Summit 2023 meeting and is only available in HTML format. There are no additional versions or additional content available for this abstract. Physiology was not involved in the peer review process.