Abstract EP46: Can Middle-Aged Recreational Cyclists Remain In Energy Balance And Weight Stable When Involved In An Extreme Exercise And Energy Expenditure Intervention (4E Study)? Effect On Visceral Adiposity And Features Of Cardiometabolic Risk

Abstract

Introduction: Weight loss is often considered a key target in lifestyle interventions aimed at reducing cardiometabolic risk in people with overweight/obesity. However, evidence suggests that regular endurance exercise can induce a mobilization of visceral fat in the absence of weight loss. Therefore, the objective of the present study was to test the effect of an extreme exercise prescription not aimed at weight loss on visceral adiposity and on indices of cardiometabolic health. Hypothesis: Despite our attempt to keep the cyclists weight stable during the 1-week exercise intervention, a loss of visceral fat would be observed. Methods: Eleven male recreational cyclists, aged 50 to 66 years and asymptomatic for cardiovascular disease, cycled 1144 km (715 miles) over a period of seven consecutive days. During the intervention, body weight and composition were assessed daily by bioelectrical impedance and cyclists’ caloric intake was increased to keep them in energy balance and weight stable. Their cardiometabolic health profile was documented before and after the intervention and included a fasting blood test, a resting hemodynamic profile, anthropometric, body composition and body fat distribution measurements including visceral adiposity assessed by magnetic resonance. A maximal cardiopulmonary exercise test was performed at baseline. During the intervention, energy expenditure was calculated from the caloric equivalents of oxygen consumption for each heart rate value acquired with a heart rate monitor. Prepared foods were provided to participants and their energy intake was closely monitored. Results: Small decreases in body weight (-0.8 kg, P <0.05), BMI (-0.3 kg/m 2 , P <0.05) and fat mass (-1.5 kg, P =0.0005) as well as a trend towards an increase in lean mass (+0.8 kg, P =0.07) were observed. Visceral adiposity (-14.1 mL, P <0.01) and waist circumference (-3.2 cm, P <0.0001) decreased while subcutaneous adiposity remained unchanged (-2.7 mL, NS). Decreases in total cholesterol (-1.17 mmol/L, P <0.001), LDL cholesterol (-0.97 mmol/L, P <0.0001), non-HDL cholesterol (-1.32 mmol/L, P <0.0001), triglycerides (-0.77 mmol/L, P <0.005), glycated hemoglobin (-0.1%, P <0.005), and resting systolic (-9 mmHg, P <0.01) and diastolic (-7 mmHg, P <0.01) blood pressure were noted. Conclusion: This study showed that recreational master cyclists were not able to remain in energy balance when exposed to a very large exercise prescription performed over one week. However, despite trivial changes in body weight and no change in subcutaneous adiposity, a significant reduction in visceral adiposity was observed. This study shows the differential response of subcutaneous vs visceral adiposity to a very large prescription of endurance exercise, and the inability of body weight changes to fully appreciate the effects of endurance exercise on features of cardiometabolic risk.