Effect of Aromatherapy on Equine Heart Rate Variability.
Authors: Baldwin Ann Linda, Chea Isabelle
Journal: Journal of equine veterinary science
Summary
# Editorial Summary: Aromatherapy and Equine Parasympathetic Tone Given horses' heightened sensitivity to environmental stressors and their well-developed olfactory system, Baldwin and Chea investigated whether inhaled essential oils could modulate autonomic nervous system activity, specifically increasing parasympathetic dominance as measured by heart rate variability (HRV). Their crossover-design study enrolled eight dressage horses exposed to humidified lavender or chamomile vapour alongside control treatments, with HRV recordings captured across multiple timepoints (baseline, during exposure, immediately post-treatment, and 30 minutes later). Lavender demonstrated statistically significant parasympathetic activation, with root mean square of successive differences (RMSSD)—the gold-standard HRV marker of vagal tone—increasing from 86.5 to 104.3 ms immediately post-exposure, alongside a corresponding reduction in very low frequency oscillations from 81.2% to 72.1%, suggesting a genuine shift toward parasympathetic dominance rather than sympathetic withdrawal. Chamomile produced inconsistent, non-significant effects across measured parameters. For practitioners managing anxious or reactive horses, these findings support lavender aromatherapy as a non-invasive adjunctive tool during potentially stressful situations such as farriery, veterinary procedures, or pre-competition periods, though the transient nature of the effect warrants consideration of timing and repeated exposure protocols in clinical application.
Read the full abstract on PubMed
Practical Takeaways
- •Lavender aromatherapy may be a practical, non-pharmacological tool to reduce acute stress responses in horses during handling, veterinary procedures, or training sessions
- •Effects are short-lived (immediate post-exposure), so timing of aromatherapy application matters if calming effect is intended
- •Chamomile did not show reliable effects in this small study, limiting recommendations for its use as an anxiolytic agent
Key Findings
- •Lavender essential oil transiently increased RMSSD (parasympathetic marker) from 86.5 ms to 104.3 ms immediately after treatment (P = 0.020)
- •Lavender reduced very low frequency HRV oscillations from 81.2% to 72.1% (P = 0.039), indicating reduced sympathetic dominance
- •Chamomile showed variable, non-significant effects on HRV parameters
- •Effects were transient, detected immediately post-treatment but not sustained at 30-minute measurement