Influence of lighting on sleep behaviour, circadian rhythm and spontaneous blink rate in stabled riding school horses (Equus caballus).
Authors: Greening Linda, Harkin Eilis, Kyriazopoulou Panoraia, Heppelthwaite Zoe, Aragona Francesca, Browne John A, Hemmings Andrew, Williams Jane M, Murphy Barbara A
Journal: PloS one
Summary
# Editorial Summary Stabled horses often endure inadequate lighting and human disturbances during their natural rest periods, raising questions about how artificial light environments affect their physiology and behaviour. Researchers compared a customised LED system (providing blue-enriched white light during the day and dim red light at night) against standard fluorescent lighting in ten riding school horses over two four-week periods, measuring sleep architecture, circadian gene expression (PER2 and DBP), and spontaneous blink rates through continuous 72-hour behavioural observation, gene sampling at four-hour intervals, and blink rate recordings. Neither lighting condition produced differences in total sleep duration, recumbency positions, wakefulness overall, or blink rates; however, the LED treatment did elicit significantly higher wakefulness during daylight hours, and both conditions demonstrated normal 24-hour circadian rhythmicity in clock gene expression regardless of lighting type. The findings suggest that introducing dim red lighting at night does not disrupt equine sleep or circadian function—a reassuring outcome for stable design—whilst the increased daytime alertness under blue-enriched LED warrants investigation as a potential tool for enhancing ridden work performance and cognitive engagement in stabled horses. These results indicate that lighting interventions merit closer examination in operational settings, particularly regarding their effects on behaviour during working hours rather than simply replicating natural photoperiods.
Read the full abstract on PubMed
Practical Takeaways
- •Blue-enriched LED lighting during the day may help keep stabled horses more alert and engaged during working hours without disrupting sleep architecture overall
- •Using dim red light at night is a safe lighting strategy that does not compromise sleep quality or circadian function in stabled horses
- •Customised LED lighting systems show promise for improving daytime behaviour in riding school horses, warranting adoption in facilities concerned with horse alertness and welfare
Key Findings
- •No significant differences in total sleep, recumbency, or blink rate between LED and fluorescent lighting conditions (P > 0.05)
- •LED blue-enriched light during day resulted in higher wakefulness during daytime hours compared to control (P < 0.05)
- •Both lighting conditions maintained significant 24-hour circadian rhythmicity for clock genes PER2 and DBP (P < 0.01)
- •Dim red light at night did not negatively impact normal sleep patterns or circadian gene expression