Exposure to bright light during evening class hours increases alertness among working college students

Author(s)

Teixeira, Liliane ^[1] ; Lowden, Arne ^[2] ; da Luz, Andrea Aparecida ^[3] ; Turte, Samantha Lemos ^[3] ; Moreno, Claudia Roberta ^[3] ; Valente, Daniel ^[1] ; Nagai-Manelli, Roberta ^[3] ; Louzada, Fernando Mazzilli ^[4] ; Fischer, Frida Marina ^[3]

Affiliation

^[1] Fiocruz MS, Natl Sch Publ Hlth, BR-21041210 Rio De Janeiro, RJ - Brazil

^[2] Stockholm Univ, Stress Res Inst, SE-10691 Stockholm - Sweden

^[3] Univ Sao Paulo, Dept Environm Hlth, BR-01246904 Sao Paulo - Brazil

^[4] Univ Fed Parana, Dept Physiol, Curitiba, Parana - Brazil

• Document type: Journal article
• Source: Sleep Medicine; v. 14, n. 1, p. 91-97, JAN 2013.
• Web of Science Citations: 6

Abstract

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 24 years, working during the day and studying in the evening, participated in this study. During the 3 week 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 21:00 h. 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 22:00 h (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 21:30 h 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. (C) 2012 Elsevier B. V. All rights reserved. (AU)

• FAPESP's process: 07/04648-4 - Study and work: consequences on health and quality of life of College students
• Grantee: Frida Marina Fischer
• Support Opportunities: Regular Research Grants