Endurance exercise induces distinct skeletal and cardiac mitochondrial adaptations in racehorses

American Journal of Physiology-Heart and Circulatory Physiology 2026 Open access

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Authors: Simon Libak Haugaard, Mélodie J. Schneider, Sarah Dalgas Nissen, Arnela Saljic, Peter Fruergaard Andersen, Helena Carstensen, Charlotte C. S. Hopster-Iversen, Thomas Jespersen, S. Larsen, Rikke Buhl
DOI: 10.1152/ajpheart.00833.2025
Cited by: 1
References: 103

Abstract

This study reveals how endurance training shapes mitochondrial function in the heart and skeletal muscle. Using racehorses as a natural large-animal model, we compared mitochondrial respiration across all four cardiac chambers and skeletal muscle. Skeletal muscle mitochondria from trained horses showed greater respiratory capacity, whereas cardiac mitochondria did not. These findings uncover tissue-specific metabolic adaptations to exercise and highlight how cardiac energetics may influence susceptibility to atrial fibrillation in endurance athletes.

Fields of Study & Subjects

Veterinary Equine Medical Research Cardiovascular Effects of Exercise Cardiovascular and exercise physiology

Publication details

Journal / source
American Journal of Physiology-Heart and Circulatory Physiology
Publisher
American Physiological Society
Volume
330
Issue
2
Pages
H531–H544
Publication date
12 January 2026
Language
EN