Skipping breakfast: gender effects on resting heart rate measures in preadolescents

Abstract

The cardiovascular response in children to morning nutrition has received little attention, and associated gender-related effects are virtually uninvestigated. This study evaluated resting heart-rate (HR) and heart-rate variability (HRV) in preadolescents after overnight fasting and again after eating a standardized breakfast or continuing to fast. For both sexes HR increased slightly after eating and decreased significantly with continued fasting (p<.01). Relative to children who ate, those who continued fasting showed increases in HRV—particularly for inter-beat-interval and low frequency component (LF: 0.04–0.15Hz) measures. There were significant increases across variability measures for fasting children (p<.01), but a selective LF decrease in those who were fed—an effect most prominent in females. Otherwise, males and females showed similar treatment-related changes in HRV. While within-gender comparisons showed similar HR results, i.e., faster HR in fed compared with fasting children, fasting females—but not males—showed significantly greater increases in variability relative to females who were fed (p<.05). The observed gender differences appear to result from greater parasympathetic activity in males and an apparent emphasis on parasympathetic regulation of LF variability. Together, these findings suggest that extended overnight fasting initiates an increase in parasympathetic activity that attenuates the expected increase in cardiovascular output following a mid-morning meal. Supported by USDA CRIS 6251-51000-002-03S