{"status":"ok","message-type":"work","message-version":"1.0.0","message":{"indexed":{"date-parts":[[2026,9,19]],"date-time":"2026-09-19T01:55:11Z","timestamp":1789782911571,"version":"4.0.1"},"reference-count":73,"publisher":"Public Library of Science (PLoS)","issue":"6","license":[{"start":{"date-parts":[[2025,6,27]],"date-time":"2025-06-27T00:00:00Z","timestamp":1750982400000},"content-version":"vor","delay-in-days":0,"URL":"http:\/\/creativecommons.org\/licenses\/by\/4.0\/"}],"funder":[{"DOI":"10.13039\/100001250","name":"Morris Animal Foundation","doi-asserted-by":"publisher","award":["D22EQ-514"],"award-info":[{"award-number":["D22EQ-514"]}],"id":[{"id":"10.13039\/100001250","id-type":"DOI","asserted-by":"publisher"}]}],"content-domain":{"domain":["www.plosone.org"],"crossmark-restriction":false},"short-container-title":["PLoS One"],"abstract":"<jats:p>\n                    Modern horse husbandry involves significant time spent indoors, often in suboptimal lighting conditions and with frequent night-time disturbances by humans for management purposes. The aim of this study was to investigate the influence of a customised light-emitting diode (LED) lighting system and a standard fluorescent lighting fixture on equine sleep behaviours, circadian rhythmicity and spontaneous blink rates in horses. Ten riding school horses experienced two stable lighting conditions for four weeks each in a cross-over study running from January to March, 2023. The treatment lighting consisted of an LED system that provided timed, blue-enriched white polychromatic light by day and dim red light at night, and control lighting was a fluorescent tube that was turned on and off manually morning and evening. During week 4 of each experimental period, spontaneous blink rate was recorded twice for 30\u2009min, behaviour of horses in their stables was recorded continuously for 72\u2009h, and hair samples for circadian clock gene analysis were collected at 4-h intervals for 52\u2009h. No differences were detected for total sleep, lateral or sternal recumbency, wakefulness, standing, standing sleep, or spontaneous blink rate (P\u2009&gt;\u20090.05), between lighting conditions. The lighting period (Day versus Night) influenced total sleep (P\u2009&lt;\u20090.01), total recumbency (P\u2009&lt;\u20090.01), wakefulness (P\u2009&lt;\u20090.01), and standing sleep (P\u2009&lt;\u20090.05) in both conditions. For the treatment condition only, higher wakefulness was recorded during Day (P\u2009&lt;\u20090.05). An overall effect of time for clock genes\n                    <jats:italic>PER2<\/jats:italic>\n                    and\n                    <jats:italic>DBP<\/jats:italic>\n                    was detected (P\u2009&lt;\u20090.01), but there was no effect of treatment, or time by treatment interaction. Cosinor analysis detected significant 24-h rhythmicity for\n                    <jats:italic>PER2<\/jats:italic>\n                    and\n                    <jats:italic>DBP<\/jats:italic>\n                    (P\u2009&lt;\u20090.01) in both lighting conditions. Results imply that dim red light at night does not negatively impact normal sleep patterns or circadian rhythmicity, and provide evidence supporting further research to better understand the role of blue-enriched LED light at promoting increased wakefulness during daytime in stabled horses.\n                  <\/jats:p>","DOI":"10.1371\/journal.pone.0326567","type":"journal-article","created":{"date-parts":[[2025,6,27]],"date-time":"2025-06-27T13:44:16Z","timestamp":1751031856000},"page":"e0326567","update-policy":"https:\/\/doi.org\/10.1371\/journal.pone.corrections_policy","source":"Crossref","is-referenced-by-count":5,"title":["Influence of lighting on sleep behaviour, circadian rhythm and spontaneous blink rate in stabled riding school horses (Equus caballus)"],"prefix":"10.1371","volume":"20","author":[{"given":"Linda","family":"Greening","sequence":"first","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Eilis","family":"Harkin","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0001-7029-5973","authenticated-orcid":true,"given":"Panoraia","family":"Kyriazopoulou","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Zoe","family":"Heppelthwaite","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Francesca","family":"Aragona","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"John A.","family":"Browne","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Andrew","family":"Hemmings","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"given":"Jane M.","family":"Williams","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]},{"ORCID":"https:\/\/orcid.org\/0000-0003-2163-7927","authenticated-orcid":true,"given":"Barbara A.","family":"Murphy","sequence":"additional","affiliation":[],"role":[{"vocabulary":"crossref","role":"author"}]}],"member":"340","published-online":{"date-parts":[[2025,6,27]]},"reference":[{"key":"pone.0326567.ref001","doi-asserted-by":"crossref","first-page":"28","DOI":"10.1016\/j.applanim.2017.02.019","article-title":"Rider impacts on equitation","volume":"190","author":"J Williams","year":"2017","journal-title":"Appl Anim Behav Sci"},{"key":"pone.0326567.ref002","first-page":"196","article-title":"Behavioural problems with the ridden horse.","volume-title":"The domestic horse: The origins, development and management of its behaviour","author":"PD McGreevy","year":"2005"},{"key":"pone.0326567.ref003","author":"BETA","year":"2023"},{"key":"pone.0326567.ref004","doi-asserted-by":"crossref","first-page":"105","DOI":"10.1016\/j.applanim.2016.04.015","article-title":"How to keep your horse safe? An epidemiological study about management practices","volume":"181","author":"C Lesimple","year":"2016","journal-title":"Appl Anim Behav Sci"},{"key":"pone.0326567.ref005","doi-asserted-by":"crossref","first-page":"105229","DOI":"10.1016\/j.applanim.2021.105229","article-title":"The effect of altering routine husbandry factors on sleep duration and memory consolidation in the horse","volume":"236","author":"L Greening","year":"2021","journal-title":"Appl Anim Behav Sci"},{"issue":"7","key":"pone.0326567.ref006","doi-asserted-by":"crossref","DOI":"10.1242\/bio.059964","article-title":"Towards an objective measurement of sleep quality in non-human animals: using the horse as a model species for the creation of sleep quality indices","volume":"12","author":"L Greening","year":"2023","journal-title":"Biol Open"},{"key":"pone.0326567.ref007","doi-asserted-by":"crossref","first-page":"68","DOI":"10.1016\/j.nbscr.2018.02.003","article-title":"Sleep homeostasis and the circadian clock: Do the circadian pacemaker and the sleep homeostat influence each other\u2019s functioning?","volume":"5","author":"T Deboer","year":"2018","journal-title":"Neurobiol Sleep Circadian Rhythms"},{"key":"pone.0326567.ref008","doi-asserted-by":"crossref","first-page":"916737","DOI":"10.3389\/fvets.2022.916737","article-title":"A review of equine sleep: Implications for equine welfare","volume":"9","author":"L Greening","year":"2022","journal-title":"Front Vet Sci"},{"issue":"1","key":"pone.0326567.ref009","doi-asserted-by":"crossref","first-page":"193","DOI":"10.3390\/clockssleep1010017","article-title":"Light modulation of human clocks, wake, and sleep","volume":"1","author":"AS Prayag","year":"2019","journal-title":"Clocks Sleep"},{"issue":"6","key":"pone.0326567.ref010","article-title":"Light, sleep, and circadian rhythms: together again","volume":"7","author":"D-J Dijk","year":"2009","journal-title":"PLoS 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degenerate mice","volume":"125","author":"RJ Lucas","year":"2001","journal-title":"Behav Brain Res"},{"issue":"11","key":"pone.0326567.ref015","first-page":"2783","article-title":"Organization and function of a central nervous system circadian oscillator: the suprachiasmatic hypothalamic nucleus","volume":"42","author":"RY Moore","year":"1983","journal-title":"Fed Proc"},{"issue":"4945","key":"pone.0326567.ref016","doi-asserted-by":"crossref","first-page":"975","DOI":"10.1126\/science.2305266","article-title":"Transplanted suprachiasmatic nucleus determines circadian period","volume":"247","author":"MR Ralph","year":"1990","journal-title":"Science"},{"issue":"8","key":"pone.0326567.ref017","doi-asserted-by":"crossref","first-page":"3111","DOI":"10.1073\/pnas.0409734102","article-title":"Differential control of peripheral circadian rhythms by suprachiasmatic-dependent neural signals","volume":"102","author":"H Guo","year":"2005","journal-title":"Proc Natl Acad Sci U S 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A"},{"issue":"11","key":"pone.0326567.ref021","doi-asserted-by":"crossref","first-page":"1029","DOI":"10.1016\/j.cub.2012.04.009","article-title":"In vivo monitoring of peripheral circadian clocks in the mouse","volume":"22","author":"Y Tahara","year":"2012","journal-title":"Curr Biol"},{"issue":"15","key":"pone.0326567.ref022","doi-asserted-by":"crossref","first-page":"5339","DOI":"10.1073\/pnas.0308709101","article-title":"PERIOD2::LUCIFERASE real-time reporting of circadian dynamics reveals persistent circadian oscillations in mouse peripheral tissues","volume":"101","author":"S-H Yoo","year":"2004","journal-title":"Proc Natl Acad Sci U S A"},{"issue":"1","key":"pone.0326567.ref023","doi-asserted-by":"crossref","first-page":"7","DOI":"10.1186\/1740-3391-10-7","article-title":"Investigation of a non-invasive method of assessing the equine circadian clock using hair follicle cells","volume":"10","author":"LM Watts","year":"2012","journal-title":"J Circadian 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Neurol"},{"issue":"10","key":"pone.0326567.ref027","doi-asserted-by":"crossref","first-page":"939","DOI":"10.1007\/BF01953051","article-title":"Mammalian pineal melatonin: a clock for all seasons","volume":"45","author":"TJ Bartness","year":"1989","journal-title":"Experientia"},{"issue":"4","key":"pone.0326567.ref028","doi-asserted-by":"crossref","first-page":"258","DOI":"10.1111\/j.1742-7843.2006.00032.x","article-title":"Orally administered melatonin improves nocturnal rest in young and old ringdoves (Streptopelia risoria)","volume":"100","author":"SD Paredes","year":"2007","journal-title":"Basic Clin Pharmacol Toxicol"},{"key":"pone.0326567.ref029","doi-asserted-by":"crossref","first-page":"126","DOI":"10.1159\/000110635","article-title":"The immune-pineal axis: a shuttle between endocrine and paracrine melatonin sources","volume":"14","author":"RP Markus","year":"2007","journal-title":"Neuroimmunomodulation"},{"key":"pone.0326567.ref030","doi-asserted-by":"crossref","first-page":"94","DOI":"10.1016\/j.lfs.2017.02.008","article-title":"Association between light at night, melatonin secretion, sleep deprivation, and the internal clock: Health impacts and mechanisms of circadian disruption","volume":"173","author":"Y Touitou","year":"2017","journal-title":"Life Sci"},{"issue":"5","key":"pone.0326567.ref031","doi-asserted-by":"crossref","first-page":"379","DOI":"10.1177\/0748730408323089","article-title":"Sensitivity of the human circadian system to short-wavelength (420-nm) light","volume":"23","author":"GC Brainard","year":"2008","journal-title":"J Biol Rhythms"},{"key":"pone.0326567.ref032","doi-asserted-by":"crossref","DOI":"10.1016\/B978-0-12-396971-2.10000-4","article-title":"Introduction to biological timing in health and disease.","volume-title":"Chronobiology: Biological timing in health and disease","author":"M. Gillette","year":"2013"},{"issue":"12","key":"pone.0326567.ref033","doi-asserted-by":"crossref","first-page":"23448","DOI":"10.3390\/ijms151223448","article-title":"Protecting the melatonin rhythm through circadian healthy light exposure","volume":"15","author":"MA Bonmati-Carrion","year":"2014","journal-title":"Int J Mol Sci"},{"key":"pone.0326567.ref034","article-title":"Light, Photoreceptors, and Circadian Clocks.","volume-title":"Circadian Rhythms. 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activity","volume":"18","author":"U Redlin","year":"2001","journal-title":"Chronobiol Int"},{"key":"pone.0326567.ref038","doi-asserted-by":"crossref","first-page":"5","DOI":"10.1186\/1740-3391-5-5","article-title":"Rapid phase adjustment of melatonin and core body temperature rhythms following a 6-h advance of the light\/dark cycle in the horse","volume":"5","author":"BA Murphy","year":"2007","journal-title":"J Circadian Rhythms"},{"key":"pone.0326567.ref039","doi-asserted-by":"crossref","first-page":"105360","DOI":"10.1016\/j.tvjl.2019.105360","article-title":"Red light at night permits the nocturnal rise of melatonin production in horses","volume":"252","author":"BA Murphy","year":"2019","journal-title":"Vet J"},{"issue":"3","key":"pone.0326567.ref040","doi-asserted-by":"crossref","first-page":"91","DOI":"10.2114\/jpa.17.91","article-title":"The influence of different wavelengths of light on human biological rhythms","volume":"17","author":"T Morita","year":"1998","journal-title":"Appl Human Sci"},{"key":"pone.0326567.ref041","doi-asserted-by":"crossref","first-page":"829351","DOI":"10.1155\/2010\/829351","article-title":"The effects of red and blue lights on circadian variations in cortisol, alpha amylase, and melatonin","volume":"2010","author":"MG Figueiro","year":"2010","journal-title":"Int J Endocrinol"},{"key":"pone.0326567.ref042","doi-asserted-by":"crossref","first-page":"35662","DOI":"10.1038\/srep35662","article-title":"Dim light at night disturbs the daily sleep-wake cycle in the rat","volume":"6","author":"DJ Stenvers","year":"2016","journal-title":"Sci Rep"},{"issue":"7","key":"pone.0326567.ref043","doi-asserted-by":"crossref","first-page":"1333","DOI":"10.1007\/s00125-017-4262-y","article-title":"Light at night acutely impairs glucose tolerance in a time-, intensity- and wavelength-dependent manner in rats","volume":"60","author":"A-L Opperhuizen","year":"2017","journal-title":"Diabetologia"},{"issue":"5","key":"pone.0326567.ref044","doi-asserted-by":"crossref","DOI":"10.1038\/lsa.2016.231","article-title":"Red light at intensities above 10\u2009lx alters sleep-wake behavior in mice","volume":"6","author":"Z Zhang","year":"2017","journal-title":"Light Sci Appl"},{"issue":"3","key":"pone.0326567.ref045","doi-asserted-by":"crossref","first-page":"143","DOI":"10.1016\/j.slsci.2015.09.002","article-title":"Interactions between sleep, stress, and metabolism: From physiological to pathological conditions","volume":"8","author":"C Hirotsu","year":"2015","journal-title":"Sleep Sci"},{"key":"pone.0326567.ref046","doi-asserted-by":"crossref","first-page":"113896","DOI":"10.1016\/j.physbeh.2022.113896","article-title":"The impulsive horse: Comparing genetic, physiological and behavioral indicators to those of human addiction","volume":"254","author":"SD McBride","year":"2022","journal-title":"Physiol 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horses","volume":"271","author":"L Evans","year":"2024","journal-title":"Appl Anim Behav Sci"},{"issue":"1","key":"pone.0326567.ref051","doi-asserted-by":"crossref","first-page":"54","DOI":"10.2478\/fv-2021-0007","article-title":"Monitoring of Stress in Police Horses","volume":"65","author":"M Lell\u00e1kov\u00e1","year":"2021","journal-title":"Folia Veterinaria"},{"issue":"5","key":"pone.0326567.ref052","doi-asserted-by":"crossref","DOI":"10.1371\/journal.pone.0294089","article-title":"Evaluation of short-term hair follicle storage conditions for maintenance of RNA integrity","volume":"19","author":"EE Harkin","year":"2024","journal-title":"PLoS One"},{"issue":"4","key":"pone.0326567.ref053","doi-asserted-by":"crossref","first-page":"275","DOI":"10.1080\/09291010600903692","article-title":"Procedures for numerical analysis of circadian rhythms","volume":"38","author":"R Refinetti","year":"2007","journal-title":"Biol Rhythm 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Open"},{"key":"pone.0326567.ref063","article-title":"Quantifying equid behavior\u2014a research ethogram for free-roaming feral horses","volume":"26","author":"JI Ransom","year":"2009","journal-title":"US Geol Surv Tech Methods"},{"issue":"3","key":"pone.0326567.ref064","doi-asserted-by":"crossref","first-page":"630","DOI":"10.1111\/j.1939-1676.2008.0096.x","article-title":"Qualitative and quantitative characteristics of the electroencephalogram in normal horses during spontaneous drowsiness and sleep","volume":"22","author":"DC Williams","year":"2008","journal-title":"J Vet Intern Med"},{"key":"pone.0326567.ref065","doi-asserted-by":"crossref","first-page":"1","DOI":"10.1016\/j.jveb.2023.10.003","article-title":"Stable design influences relaxation and affiliative behavior in horses during short isolation bouts","volume":"69","author":"EJ Borthwick","year":"2023","journal-title":"J Vet Behav"},{"key":"pone.0326567.ref066","first-page":"180","article-title":"Sleep and sleep disorders in 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