Exposure to bright light during evening class hours increases alertness among working college students
2013 (English)In: Sleep Medicine, ISSN 1389-9457, E-ISSN 1878-5506, Vol. 14, no 1, 91-97 p.Article in journal (Refereed) Published
OBJECTIVE: To evaluate the effects of exposure to bright light on sleepiness during evening hours among college students. METHODS: Twenty-seven healthy college students, all males, with ages ranging from 21 to 24years, working during the day and studying in the evening, participated in this study. During the 3week study, the students wore actigraphs and recorded levels of sleepiness. In a crossover design, on the second and third weeks, the students were exposed to bright light (BL) at either 19:00 or 21:00h. Salivary melatonin samples were collected before and after BL exposure. ANOVA test for repeated measurements were performed. RESULTS: After BL exposure, sleepiness levels were reduced at 20:30 and 22:00h (F=2.2; p<0.05). ANOVA showed statistical differences between time (F=4.84; p=0.04) and between day and time of BL exposure (F=4.24; p=0.05). The results showed effects of melatonin onset at 20:00 and 21:30h and sleepiness levels (F=7.67; p=0.02) and perception of sleepiness and intervention time (F=6.52; p=0.01). CONCLUSION: Controlled exposure to BL during evening hours increased alertness among college students. The effects of BL on sleepiness varied according to the time of melatonin onset.
Place, publisher, year, edition, pages
2013. Vol. 14, no 1, 91-97 p.
bright light intervention, melatonin, sleepiness, morningness-eveningness, sleep-wake cycle, working college students
Other Medical Sciences
IdentifiersURN: urn:nbn:se:su:diva-82575DOI: 10.1016/j.sleep.2012.08.017ISI: 000313727100016PubMedID: 23127584Local ID: P2956OAI: oai:DiVA.org:su-82575DiVA: diva2:570466