HOSTED BY www.elsevier.com/locate/ssci Available online at www.sciencedirect.com Temporal sleep patterns in adults using actigraph Lia Matuzaki a , Rogerio Santos-Silva a,n , Elaine Cristina Marqueze b , Claudia Roberta de Castro Moreno b , Sergio Tufik a , Lia Bittencourt a a Departamento de Psicobiologia, Universidade Federal de São Paulo. Rua Napoleão de Barros 925, CEP 04024-002, São Paulo/SP, Brazil b Environmental Health Department, School of Public Health, University of São Paulo. Av. Dr. Arnaldo 715, CEP 01246-904, São Paulo/SP, Brazil article info Available online 5 October 2014 Keywords: Temporal patterns Actigraph Circadian preferences Sleep-wake pattern Morningness Eveningness abstract The aim of the present study was to characterize the temporal patterns of sleep and wakefulness in a sample of the adult subjects from São Paulo city. All subjects filled the Morningness/Eveningness Questionnaire (MEQ) and wore an actigraph for at least three consecutive days. A total of 359 subjects were considered for the analyses. The mean age was 43714 years, the mean body mass index was 26.775.7 kg/m 2 , and 60% were female. The mean MEQ score was 58.0710.7. The sleep pattern evaluated by the actigraphic analyses showed that 92% had a monophasic sleep pattern, 7% biphasic, and 1% polyphasic sleep pattern. Cluster analysis, based on time to sleep onset, sleep efficiency, sleep latency, and total sleep time, was able to identify three different groups denominated: morning type, evening type, and undefined type. Morning type subjects were more frequent, older, and had higher MEQ scores than evening type subjects. Our results showed that the actigraph objectively assessed the sleep-wake cycle and was able to discriminate between morning and evening type individuals. These findings suggest that the actigraph could be a valuable tool for assessing temporal sleep patterns, including the circadian preferences. & 2014 Published by Elsevier B.V. on behalf of Brazilian Association of Sleep. 1. Introduction Few epidemiological studies have evaluated the pattern of sleep-wake cycle in the general population. Questionnaires or sleep logs, in addition to the objective evaluation of sleep- wake patterns by actigraphs, are typically used in these studies [1–5]. It is important to note that the results of actigraphic recording as an instrument to investigate sleep pattern has been compared with polysomnography, which is considered the gold standard for objective evaluation of sleep, showing good correlation [6,7]. Previous studies have shown that duration and quality of sleep, which have consequences for health, are strongly associated with race, gender, and socioeconomic status [1]. It has also been demonstrated that the self-reported sleep duration is longer than the sleep duration objectively evaluated using an acti- graph [2] and that morningness/eveningness preference is largely independent of ethnicity, gender, and socioeconomic status, indicating that this preference may be better explained by endogenous factors [3]. However, past studies with young adults showed female had significantly stronger tendency toward the morningness preference, and the authors considered the role of social-cultural factors in the existence of gender differences [4,5]. http://dx.doi.org/10.1016/j.slsci.2014.09.012 1984-0063/& 2014 Published by Elsevier B.V. on behalf of Brazilian Association of Sleep. n Correspondence to: Rua Napoleão de Barros 925, CEP 04024-002, São Paulo/SP, Brazil. Tel.: þ55 11 21490155; fax: þ55 11 55725092. E-mail address: roger.ss@uol.com.br (R. Santos-Silva). Peer review under responsibility of Brazilian Association of Sleep. Sleep Science 7 (2014) 152–157