Improved Cardio-Respiratory Fitness Correlates with Changes in the Number and Size of Small Dense LDL: Randomized Controlled Trial with Exercise Training and Dietary Instruction

Objective To investigate the correlation between lifestyle improvements, in particular increased cardiorespiratory fitness and changes in the blood lipid profile. Methods The participants were 217 residents of Fuji and Yamato Towns, Saga City, with mildly abnormal blood pressure, serum lipids or blood glucose detected at health check-ups in 2003. Participants were randomly allocated to an Intervention (108 subjects) or Control group (109 subjects), matched for age and various conditions. The Intervention group was given exercise advice and prescription and dietary instructions. Cardio-respiratory fitness was evaluated using the work rate at double product breaking point. Changes of lipid parameters were compared before and after intervention, and examined the relationship with cardiorespiratory fitness. Results Seventy nine subjects in each group could be followed up for 17 months without requiring pharmacotherapy. Body mass index, waist circumference, systolic blood pressure, homeostasis model assessment insulin resistance, and triglycerides were decreased in the Intervention group. Furthermore, apolipoprotein B levels were lower (p<0.05), and the ratio of LDL cholesterol to apolipoprotein B (LDL/ApoB) was higher (p<0.001). When all subjects were divided into 3 subgroups according to the degree of improvement in cardio-respiratory fitness, LDL/ApoB increased and apolipoprotein B decreased as the degree of improvement increased (p<0.05). Conclusion Improvement was seen in atherosclerotic risk factors through lifestyle modification. In particular, improved cardiorespiratory fitness was associated with qualitative and quantitative changes in LDLs.