[Prevalence and factors associated with the co-occurrence of health risk behaviors in adolescents].

Objective:: To analyze the prevalence and factors associated with the co-occurrence of health risk behaviors in adolescents.

Methods:: A cross-sectional study was performed with a sample of high school students from state public schools in Pernambuco, Brazil (=4207, 14-19 years old). Data were obtained using a questionnaire.

Intra-individuals and inter- and intra-observer reliability of short-term heart rate variability in adolescents.

Background: To examine the reliability of heart rate variability (HRV) parameters in adolescents and to analyse the inter- and intra-observer reliability of data analysis.

Methods: The sample included 27 adolescents aged 14-19 years old. RR intervals were obtained for 10 min in the supine position on two different days (Day 1 and Day 8) with an interval of 7 days to analyse intra-individual reliability.