Abstract
OBJECTIVE: The current study describes sleeping heart rate patterns in an adolescent cohort of Hispanic and Caucasian children over approximately a 5-year period to determine how sex, ethnicity, and body mass index (BMI) contribute to sleeping heart rate patterns over time. METHODS: Participants were recruited from a large urban school district in the southwest United States as part of the Tucson Children's Assessment of Sleep Apnea Study (TuCASA). Heart rate data was obtained through electrocardiogram (ECG) recordings during in-home polysomnography, approximately 5 years apart. Second-wave cohort data were analyzed to determine how age, sex, ethnicity, physical activity, and BMI contribute to average sleeping heart rates. The same variables were used to investigate how sleeping heart rate patterns change longitudinally from school-age (6-11 years) to adolescence (10-17 years) during sleep. RESULTS: Female adolescents had significantly faster average heart rates during sleep. Sleeping heart rate decreased significantly with increasing age in the adolescent cohort. Although the Hispanic group had a statistically significant higher body mass index than Caucasians, there were no significant differences in heart rate observed between ethnicities or in those who were classified as obese (BMI ≥ 95(th) percentile for age). Longitudinal analysis between the school-aged and adolescent cohort revealed a significant overall decrease in heart rate across a 5-year period. CONCLUSIONS: Hispanic and Caucasian adolescents experience a similar decrease in sleeping heart rate with age. Female adolescents had significantly faster heart rates than males, and no significant differences were observed between Caucasians and Hispanics, or obese vs. nonobese adolescents.