Exercise-induced alterations in plasma concentrations of ghrelin, adiponectin, leptin, glucose, insulin, and cortisol in horses.
Authors: Gordon Mary E, McKeever Kenneth H, Betros Cynthia L, Manso Filho Helio C
Journal: Veterinary journal (London, England : 1997)
Summary
# Exercise-induced alterations in plasma concentrations of ghrelin, adiponectin, leptin, glucose, insulin, and cortisol in horses Six mature Standardbred mares were subjected to incremental exercise tests to maximal oxygen uptake alongside control trials, with blood sampling at multiple timepoints during and up to 24 hours post-exercise to investigate how short-term, high-intensity work influences metabolic and endocrine hormones. During the exercise itself, cortisol increased significantly by 29% whilst insulin dropped by 35%, though glucose, leptin, adiponectin and ghrelin remained unchanged; the post-exercise period proved more revealing, with glucose and cortisol surging 36% and 102% respectively within the first hour, whilst leptin concentrations were suppressed by 20% at 24 hours compared to resting control values. Ghrelin showed a particularly dynamic response, initially 37% lower during exercise and the immediate recovery period but rebounding 43% above baseline at 12 hours post-exercise. These alterations in appetite-regulating hormones—specifically the sustained leptin depression and the dramatic ghrelin rebound—suggest that high-intensity exercise triggers physiological signals promoting increased feed intake during recovery, potentially explaining the enhanced appetite often observed in hard-worked horses. For practitioners managing equine conditioning programmes, these findings support the practice of strategic feeding post-exercise, as the hormonal environment actively encourages energy replenishment during the critical recovery window rather than opposing it.
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Practical Takeaways
- •High-intensity exercise triggers significant hormonal shifts that may increase appetite up to 12 hours post-exercise; adjust feeding timing and amounts accordingly to support recovery
- •The 24-hour post-exercise reduction in leptin suggests prolonged changes in satiety signals; monitor feed intake patterns for several hours after intense work
- •Cortisol elevation persists for at least 60 minutes after exercise; allow adequate recovery time before resuming work or training
Key Findings
- •Short-term high-intensity exercise increased plasma cortisol by 29% during exercise and 102% in the first 60 minutes post-exercise
- •Plasma insulin decreased by 35% during exercise but showed no differences between exercise and control trials during recovery
- •Plasma leptin concentration was 20% lower at 24 hours post-exercise compared to control
- •Plasma ghrelin concentration was 37% lower before and after meals in the exercise trial but 43% higher at 12 hours post-exercise, suggesting altered energy intake signaling