Effects of daily activities in patterns of sleepiness among working and non-working high school students in São Paulo

Author(s)

Liliane Reis Teixeira

• Document type: Doctoral Thesis
• Press: São Paulo.
• Institution: Universidade de São Paulo (USP). Faculdade de Saúde Pública (FSP/CIR)
• Defense date: 2006-11-07

Examining board members

Frida Marina Fischer; Miriam Mendonça Morato de Andrade; Claudia Roberta de Castro Moreno; Vilma Sousa Santana; Ana Amélia Benedito Silva

• Advisor: Frida Marina Fischer

Abstract

Introduction – Sleepiness is described as an interaction between the circadian phase and the increase in pressure to sleep. In general, it is associated with a decrease in alertness levels, reaction time, memory, psychomotor coordination, information assimilation, time to take decisions, and larger consumption of stimulant and alcoholic substances. In adolescence, sleepiness restricts the adolescent’s perspectives as to his/her intellectual development. Knowledge on perception of sleepiness in working students is poor. Objective – Verifying patterns of sleepiness along the day and the possible impact of daily activities and life styles on sleepiness among working and non-working students. Methods – The population studied comprised working and non-working high school students attending evening classes (19:00-22.30pm) at a public school in São Paulo, Brazil. The study group consisted of working and non-working students aged 14-21. The students selected filled in a questionnaire on living conditions, health and sleep, morningness-eveningness, characterization of working conditions, and frequency of food consumption. As a second step, records of their sleep-wake cycle were obtained through subjective methods (daily protocol of activities, sleep diary and sleepiness scale), as well as objective methods (Actigraphy). Socio-demographic, life style, work conditions and sleep-wake cycle variables were tested with the use of three-way ANOVA test (week day, time and work), Person’s Qui-Square test (c2) and regression analysis. Results - 1) The average sleep duration for working students during weekdays was around 7 hours, whereas the sleep duration for non-working students was around 9 hours; 2) working students’ sleepiness patterns are different from those of non-working students. We found that working students were sleepier than non-working students in the first period (07:00am-09:00am) and in the last period recorded (10:00pm-12:00pm). We also found that working students were sleepier on specific days: on Mondays after lunch time (01:00pm-03:00pm), on Wednesdays during classes (07:00pm-09:00pm) and on Fridays before bedtime (10:00pm-12:00pm). The highest level of sleepiness among students was found on Sundays, between 10:00pm-12:00pm. Also, at this time period working students in general were sleepier than non-working students, independently of the period and time of the day. 3) Other factors associated with sleepiness were: work, being a female, alcohol consumption, easiness of sleeping and going to bed after midnight. Conclusions – The sleepiness patterns for working students are different from those for non-working students, and the sleep-wake cycle variables interfere in sleepiness levels during the day. In addition to chronobiological factors, there are other factors associated with changes in sleepiness levels: a) individual factors; b) social factors; c) socio-demographic factors; and d) life style. All these factors contribute to increase in working students’ sleepiness at the beginning and end of the day; this may interfere in their school performance, impairing their physical and mental development, which is characteristic of adolescence. Intervention programs, such as those that provide information on sleep hygiene, and those related to social insertion, which would allow students to maintain and adequate life standard without having to be submitted to extended work journeys, should be implemented. (AU)