title: Reliability and variability of indicators of heart-rate monitoring in children.
abstract: We describe the daily heart-rate patterns and the between-day and within-day reliabilities of several heart rate indicators measured in 131 Anglo-, African-, and Mexican-American children aged 5-7 yr. Heart rates were measured over 12 waking hours with a Quantum XL Telemetry heart rate monitor. The percent of heart rates 25% above resting heart rate, an index of physical activity heart rate (PAHR-25 index), was found to have the highest within-day (0.92) and between-day (0.81) reliabilities. The Spearman-Brown prophecy formula indicated that only 9.3 h of observation would be needed to maintain a within-day reliability of 0.90. The percentage of heart rates 50% above resting heart rate (PAHR-50) was found to have slightly lower within-day (0.88) and between-day (0.56) reliability. Principal components analysis revealed that the PAHR-25 and PAHR-50 indicies only had one component throughout the day. The PAHR-25 and PAHR-50 indicies were weakly correlated with age, suggesting that they may be good indicators of relative PAHR. Male children had higher (P < or = 0.025) PAHR-25 index scores than females. There were no gender or ethnic differences in the PAHR-50 index.
authors.affiliation: Department of Pediatrics, Medical College of Georgia, Augusta 30912.
authors.forename: R H
authors.initials: RH
authors.lastname: Durant
authors.forename: T
authors.initials: T
authors.lastname: Baranowski
authors.forename: H
authors.initials: H
authors.lastname: Davis
authors.forename: T
authors.initials: T
authors.lastname: Rhodes
authors.forename: W O
authors.initials: WO
authors.lastname: Thompson
authors.forename: K A
authors.initials: KA
authors.lastname: Greaves
authors.forename: J
authors.initials: J
authors.lastname: Puhl
mesh_terms: D001741:Black or African American; D000367:Age Factors; D000704:Analysis of Variance; D016009:Chi-Square Distribution; D002648:Child; D002675:Child, Preschool; D002940:Circadian Rhythm; D015444:Exercise / Q000502:physiology; D005260:Female; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D008297:Male; D017058:Mexican Americans; D005082:Physical Exertion / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology*; D015203:Reproducibility of Results; D012737:Sex Factors; D013686:Telemetry / Q000295:instrumentation*; D013997:Time Factors; D044465:White People