Changes of autonomic cardiac profile after a 3-week integrated body weight reduction program in severely obese patients.
The autonomic control of the heart is abnormal in obese subjects due to a prevalence of sympathetic over parasympathetic limb of the autonomic balance. We evaluated the effects of a short-term (3 weeks) integrated body weight reduction program (consisting of energy restricted diet and high-intensity exercise training) on heart rate variability (HRV) in severely obese, normotensive patients. The HRV was evaluated both in the time and frequency domain over a 18-hour Holter recording period obtained before and at the end of the third week. Three-week body weight reduction program reduced BMI (from 41.4 +/- 4.6 to 39.5 +/- 4.3 kg/m2, -4.6%, p<0.0001) and heart rate (from 77.8 +/- 8.6 to 73.6 +/- 8.7 b/min, p=0.0003). Significant changes in the autonomic profile were observed both in the time and frequency domain (SD of RR interval, SDRR: +16.1%; mean squared successive difference: (MSSD) +16.7%; percentage of RR intervals differing more than 50 msec from the preceding one, pNN50: +31.8%; low frequency oscillation, LF: +17.1%; high frequency oscillation, HF: +/- 18.2%). In conclusion, this study demonstrates that a short-term, integrated body weight reduction program is able to favorably modify the autonomic profile in a population of normotensive, severely obese subjects. The reduction of heart rate and the increase in parasympathetic activity may consistently contribute to a reduction of the risk of cardiovascular morbidity and of sudden cardiac death, still high in this patients' group.
Division of Cardiology, Italian Institute for Auxology, IRCCS, Milan, Italy.
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Facchini
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Malfatto
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Sala
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Silvestri
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P
Fontana
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Lafortuna
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Sartorio
D000328:Adult; D001341:Autonomic Nervous System / Q000502:physiology; D001823:Body Composition; D015992:Body Mass Index; D004038:Diet, Reducing; D015716:Electrocardiography, Ambulatory; D005081:Exercise Therapy; D005260:Female; D006321:Heart / Q000502:physiology*; D006339:Heart Rate / Q000502:physiology; D006801:Humans; D008297:Male; D009767:Obesity, Morbid / Q000503:physiopathology* / Q000628:therapy; D015431:Weight Loss / Q000502:physiology*