Heart rate, heart rate variability and behaviour of horses during air transport.
Authors: Munsters C C B M, de Gooijer J-W, van den Broek J, van Oldruitenborgh-Oosterbaan M M Sloet
Journal: The Veterinary record
Summary
# Editorial Summary: Heart Rate Response to Air Transport in Horses During an eight-hour transatlantic flight, nine horses demonstrated significant heart rate elevations at specific stages of the journey, particularly during loading into the jet stall (67±21 bpm versus a resting baseline of 40±3 bpm) and periods of in-flight turbulence, whilst cruising flight itself produced comparable rates to those at rest. Heart rate variability (HRV) parameters, often considered a refined marker of autonomic stress response, failed to differentiate between transport stages or individual horses, suggesting limited utility as a monitoring tool in this context. Notable discordance emerged between physiological and behavioural indicators: some horses displayed minimal visible stress behaviours despite elevated heart rates, whilst one notably unresponsive animal exhibited the highest absolute heart rate, highlighting the danger of relying solely on overt behavioural assessment. For equine professionals managing long-distance air transport, these findings reinforce that direct heart rate monitoring provides essential additional information beyond visual observation, and that individual variation in stress expression means standardised behavioural scoring may underestimate genuine physiological distress. Whilst air transport appears to provoke less sustained tachycardia than road haulage according to existing literature, the loading phase warrants particular attention as the most acute stressor within the journey profile.
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Practical Takeaways
- •Loading procedures cause greater physiological stress than the flight itself; consider optimizing handling during jet stall and aircraft loading to minimise stress
- •Heart rate monitoring provides more objective stress assessment than observing visible behaviour, as some horses mask stress responses behaviourally despite elevated physiological markers
- •Air transport causes less heart rate elevation than road transport according to comparative literature, supporting air as a viable transport option when available
Key Findings
- •Mean heart rate was significantly elevated during jet stall loading (67±21 bpm) compared to transit (40±3 bpm, P<0.001), with jet stall loading identified as the most stressful event
- •Heart rate also increased during aircraft loading (47±6 bpm, P=0.011), taxiing (50±8 bpm, P=0.001), and in-flight turbulence (46±7 bpm, P=0.017)
- •Heart rate variability did not differ between transport stages or between individual horses, limiting its utility as a stress indicator
- •Behaviour score and heart rate measurements did not always correlate; some horses showed high heart rates with minimal visible stress responses, suggesting HR is a more reliable stress indicator than behavioural observation alone