Abstract 12288: Sex Differences in Cardiac Adaptation to Obesity During Adolescence: A Role of Cardiopulmonary Exercise Testing

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Introduction: Heart size is known to increase in obese individuals as a physiological adaptation. Cardiac hypertrophy is also regarded as a risk factor for future adult cardiovascular disease. Sex differences of cardiac adaptation to obesity during adolescence are poorly understood. Hypothesis: Physiological cardiac responses to obesity are different between male and female adolescents. Methods: Anthropometric measurements, left ventricular mass index (LVMI; g/m 2.7 ), and cardiopulmonary exercise testing parameters were analyzed. Peak oxygen consumption (VO2), ventilatory anaerobic threshold (VAT), and submaximal sloop parameters including ΔVO2/Δheart rate (HR) and ΔHR/Δwork rate (WR) were obtained. Data are shown as mean ± standard deviation. * denotes weight-indexed value. Results: Table 1 showed enrolled obese adolescents (19 males and 40 females). ΔVO2/ΔHR and ΔHR/ΔWR are surrogates of stroke volume and HR-dependency, respectively. Males showed significantly higher pVO2, pVO2*, VAT*, ΔVO2/ΔHR, and ΔVO2*/ΔHR but lower ΔHR/ΔWR and ΔHR/ΔWR* than females, suggesting males had higher peak exercise performance, higher stroke volume, and lower HR-dependency than females. Significant correlation was noted between LVMI and VAT* only in males (p = 0.045) and between LVMI and body mass index (BMI) only in females (p = 0.006), suggesting cardiac hypertrophy may not effectively contribute to exercise performance in females (Figure 1). Cardiac hypertrophy assessed by LVMI presented different physiological significance between obese males and females. Conclusions: Cardiac adaptation to obesity occurs differently between males and females during adolescence.