{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,16]],"date-time":"2026-09-16T14:08:24Z","timestamp":1789567704607,"version":"build-2803163510"},"reference-count":98,"publisher":"Frontiers Media SA","license":[{"start":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T00:00:00Z","timestamp":1785974400000},"content-version":"vor","delay-in-days":0,"URL":"https:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"content-domain":{"domain":["frontiersin.org"],"crossmark-restriction":true},"short-container-title":["Front. Vet. Sci."],"abstract":"<jats:p>Sleep is a crucial factor for the well-being of horses, yet assessing equine sleep in common housing conditions remains challenging. This study investigated the effects of changes in horses\u2019 immediate environment and the influence of age on their sleep and resting behavior using a novel, non-invasive electroencephalography (EEG) mask. Ten horses from the teaching herd at the University of Veterinary Medicine Vienna were observed over four consecutive nights in two different housing systems (a large communal stable vs. two separate, adjacent individual stalls). Data collection included EEG recordings, video monitoring, electrocardiography for heart rate variability (HRV) analysis, and fecal cortisol metabolite (FCMs) measurements. The results showed significant differences in sleep stages and lying behavior between the two housing systems. Over time, the horses, in the single stable setting, exhibited an increase in REM sleep and lying-down frequency, while in the large barn setting, they showed longer duration of lying episodes, suggesting an adaptation effect. Younger horses exhibited more REM, N1 and N2 sleep, more complete sleep cycles and longer lying episodes compared to older horses. Objective stress monitoring via HRV analysis showed trends toward increased parasympathetic activity, while FCMs showed no significant changes. These findings suggest that housing conditions and age should be considered when assessing equine sleep as well as well-being. and reinforce the need for management practices that promote adequate rest. Further research is required to establish normative values and validate EEG protocols in equine medicine and to investigate the associations between sleep, stress, and well-being.<\/jats:p>","DOI":"10.3389\/fvets.2026.1898580","type":"journal-article","created":{"date-parts":[[2026,8,6]],"date-time":"2026-08-06T12:52:02Z","timestamp":1786020722000},"update-policy":"https:\/\/doi.org\/10.3389\/crossmark-policy","source":"Crossref","is-referenced-by-count":0,"title":["Sleep architecture and lying behavior in horses across age groups and two housing systems: an overnight non-invasive EEG study"],"prefix":"10.3389","volume":"13","author":[{"given":"Lisa","family":"Zimmer","sequence":"first","affiliation":[{"name":"Clinical Department for Small Animals and Horses, Centre for Equine Health and Research, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Johannes Peter","family":"Schramel","sequence":"additional","affiliation":[{"name":"Clinical Department for Small Animals and Horses, Centre for Small Animal Health and Research, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Manolis","family":"Lyrakis","sequence":"additional","affiliation":[{"name":"Department of Biological Sciences and Pathobiology, Platform for Bioinformatics and Biostatistics, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Dagmar S.","family":"Trachsel","sequence":"additional","affiliation":[{"name":"Clinical Department for Small Animals and Horses, Centre for Equine Health and Research, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Ulrike","family":"Auer","sequence":"additional","affiliation":[{"name":"Clinical Department for Small Animals and Horses, Centre for Small Animal Health and Research, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Michael","family":"Leschnik","sequence":"additional","affiliation":[{"name":"Clinical Department for Small Animals and Horses, Centre for Small Animal Health and Research, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Sabine","family":"Macho-Maschler","sequence":"additional","affiliation":[{"name":"Department of Biological Sciences and Pathobiology, Centre for Biological Sciences, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Monika","family":"Hotz","sequence":"additional","affiliation":[{"name":"Zaza Textill\u00f6sungen GmbH","place":["Koblach, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Hanna","family":"Wahl","sequence":"additional","affiliation":[{"name":"Equine Internal Medicine, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Susanne","family":"Brunner","sequence":"additional","affiliation":[{"name":"Equine Internal Medicine, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Rupert","family":"Palme","sequence":"additional","affiliation":[{"name":"Department of Biological Sciences and Pathobiology, Centre for Biological Sciences, University of Veterinary Medicine Vienna","place":["Vienna, Austria"]}],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jessika-M. 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