title: Exercise training associated with diet improves heart rate recovery and cardiac autonomic nervous system activity in obese children.
abstract: The purpose of this study was to test the hypotheses that in obese children: 1) hypocaloric diet (D) improves both heart rate recovery at 1 min (Δ HRR1) cfter an exercise test, and cardiac autonomic nervous system activity (CANSA) in obese children; 2) Diet and exercise training (DET) combined leads to greater improvement in both Δ HRR1 after an exercise test and in CANSA, than D alone. Moreover, we examined the relationships among Δ HRR1, CANSA, cardiorespiratory fitness and anthropometric variables (AV) in obese children submitted to D and to DET. 33 obese children (10 ± 0.2 years; body mass index (BMI) >95 (th) percentile) were divided into 2 groups: D (n=15; BMI=31 ± 1 kg/m²)) and DET (n=18; 29 ± 1 kg/m²). All children performed a maximal cardiopulmonary exercise test on a treadmill. The Δ HRR1 or LF/HF ratio (P>0.05). In contrast, the DET group showed increased peak VO₂ ( P=0.01) and improved Δ HRR1 (Δ HRR1=37.3 ± 2.6; P=0.01) and LF/HF ratio ( P=0.001). The DET group demonstrated significant relationships among Δ HRR1, peak VO₂ and CANSA (P<0.05). In conclusion, DET, in contrast to D, promoted improved ÄΔ HRR1 and CANSA in obese children, suggesting a positive influence of increased levels of cardiorespiratory fitness by exercise training on cardiac autonomic activity.
authors.affiliation: Medical School, Department of Endocrinology, University of São Paulo, Brazil. danilomprado@usp.br
authors.forename: D M
authors.initials: DM
authors.lastname: Prado
authors.forename: A G
authors.initials: AG
authors.lastname: Silva
authors.forename: I C
authors.initials: IC
authors.lastname: Trombetta
authors.forename: M M
authors.initials: MM
authors.lastname: Ribeiro
authors.forename: I C
authors.initials: IC
authors.lastname: Guazzelli
authors.forename: L N
authors.initials: LN
authors.lastname: Matos
authors.forename: M S
authors.initials: MS
authors.lastname: Santos
authors.forename: C M
authors.initials: CM
authors.lastname: Nicolau
authors.forename: C E
authors.initials: CE
authors.lastname: Negrão
authors.forename: S M
authors.initials: SM
authors.lastname: Villares
mesh_terms: D000886:Anthropometry; D001341:Autonomic Nervous System / Q000502:physiology; D001837:Body Weights and Measures; D002648:Child; D005080:Exercise Test; D005081:Exercise Therapy / Q000379:methods*; D006339:Heart Rate / Q000502:physiology*; D006801:Humans; D009765:Obesity / Q000178:diet therapy / Q000628:therapy*; D010101:Oxygen Consumption / Q000502:physiology*; D010809:Physical Fitness / Q000502:physiology