title: Glucose ingestion affects cardiac ANS in healthy subjects with different amounts of body fat.
abstract: Low-to-high frequency ratio (LF/HF) is an indirect index of sympathovagal balance derived by heart rate spectral analysis. We investigated the effect of glucose ingestion on LF/HF in 17 healthy, normotensive young subjects (9 male, 8 female) with a wide body fat content range (body fat = 29 +/- 5.9%; range = 19-42%) and a normal thyroid hormone status. Before and after an oral glucose tolerance test (OGTT), the Holter technique and indirect calorimetry allowed us to determine heart rate and substrate oxidation in all subjects. At baseline, LF/HF correlated with body fat (r = 0.60, P < 0.005), waist-to-hip ratio (r = 0.57, P < 0.01), fasting plasma insulin (r = 0.55, P < 0.04), leptin (r = 0.56, P < 0.01), and norepinephrine (r = 0.58, P < 0.009) concentrations. Age-, body fat-, content-, and fat-free mass-adjusted respiratory quotient (r = 0.59, P < 0.007) and basal metabolic rate (r = 0.61, P < 0.001) were also correlated with basal LF/HF. Along with OGTT plasma glucose, insulin and norepinephrine concentrations and basal LF/HF significantly rose at 60 min and then declined throughout the test. Area under the curve (AUC) for LF/HF correlated with body fat (r = -0.66, P < 0.004), fasting plasma leptin concentration (r = -0.57, P < 0.01), glucose induced thermogenesis (r = 0.62, P < 0.001), glucose uptake (r = 0.59, P < 0.007), and AUC for plasma norepinephrine concentration (r = 0.63, P < 0.001). Water instead of glucose ingestion does not significantly affect LF/HF (n = 8). In conclusion, our study supports the hypothesis that glucose ingestion affects LF/HF and that such change is related to the amount of body fat.
authors.affiliation: Department of Geriatric Medicine and Metabolic Diseases, II University of Naples, Italy.
authors.forename: G
authors.initials: G
authors.lastname: Paolisso
authors.forename: D
authors.initials: D
authors.lastname: Manzella
authors.forename: N
authors.initials: N
authors.lastname: Ferrara
authors.forename: A
authors.initials: A
authors.lastname: Gambardella
authors.forename: P
authors.initials: P
authors.lastname: Abete
authors.forename: M R
authors.initials: MR
authors.lastname: Tagliamonte
authors.forename: D
authors.initials: D
authors.lastname: De Lucia
authors.forename: G
authors.initials: G
authors.lastname: Furgi
authors.forename: C
authors.initials: C
authors.lastname: Picone
authors.forename: S
authors.initials: S
authors.lastname: Gentile
authors.forename: F
authors.initials: F
authors.lastname: Rengo
authors.forename: M
authors.initials: M
authors.lastname: Varricchio
mesh_terms: D000273:Adipose Tissue / Q000033:anatomy & histology* / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology*; D001786:Blood Glucose / Q000378:metabolism; D002153:Calorimetry, Indirect; D015716:Electrocardiography, Ambulatory; D004837:Epinephrine / Q000097:blood; D005260:Female; D005947:Glucose / Q000008:administration & dosage / Q000494:pharmacology*; D005951:Glucose Tolerance Test; D006329:Heart Conduction System / Q000502:physiology*; D006339:Heart Rate; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D012016:Reference Values; D012044:Regression Analysis; D012119:Respiration; D013961:Thyroid Gland / Q000502:physiology; D014630:Vagus Nerve / Q000502:physiology
chemical_list: D001786:Blood Glucose; D007328:Insulin; D005947:Glucose; D004837:Epinephrine