Heart rate variability during exercise in the horse.

The research explores the changing heart rate variability (HRV) of horses during various exercise levels using an ambulatory monitoring system.

Introduction to Heart Rate Variability (HRV)

• High HRV is associated with optimal autonomic control, meaning a body’s ability to quickly adapt to environmental variations.
• Previous research showed that increased HRV in horses, revealed by spectral analysis of heart beats intervals, suggested effective control of the heart rate by the vagus nerve (the nerve that helps control heart rhythm).

Research Methodology

• The researchers monitored the heart rates of horses using a non-invasive ambulatory system as the animals exercised on a high-speed equine treadmill.
• The treadmill protocol included increasing and then decreasing workloads: 5 minutes of rest, walking, trotting, fast trotting or cantering, returning to a slower trot, returning to walking, and finally 5 minutes of recovery.

Research Findings

• The horses exhibited a decrease in HRV during physical exertion.
• Significant individual differences were observed in the rate at which the parasympathetic nervous system (the part of the nervous system that slows heart rate) resumed control following exercise.
• The patterns of heart rate changes indicated that a nonlinear dynamical model might provide a more accurate description of the body’s response to physical demands than traditional models.

Conclusion

• The research provides useful insights into how horses’ HRV changes during exercise, and highlights the potential for a more dynamic approach to modeling heart rate responses to physical stress in animals.