THE EFFECTS OF SPEED AND PATTERNS OF WALKING ON AEROBIC CAPACITY AND CORONARY HEART DISEASE RISK PROFILES IN MIDDLE-AGED OVERWEIGHT AND OBESE INDIVIDUALS

Abstract

The aim of this study was to investigate the effects of speed and the patterns of walking on aerobic capacity and Coronary Heart Disease (CHD) risk profiles in middle-aged overweight and obese individuals. Sixty-nine overweight and obese volunteers, 16 males and 53 females, aged 40-60 years old with at least 2 risk factors for CHD were recruited for this study. A simple randomization technique was employed to allocate the subjects into one of the three specific groups, Group A: a speed of 70% walking speed; Group B: a speed of 80% of walking speed; Group C: Self-paced walking. All groups performed Bruce ramp protocol at pre- and port-training to assess aerobic capacity, ventilator threshold, and physiological responses. Group A and Group B underwent Intermittent Treadmill Walk Test (ITWT) to determine maximal walking speed and 70% and 80% speed of maximal walking speed. Energy expenditure was calculated and specific walk time for each group was determined. Baseline characteristics were expressed in mean and standard deviation (SD). Intra-group differences at pre- and post-training in morphological, physiological, and hematological variables were analyzed by paired t-test. The One-way ANOVA was employed to determine the variability of the data among the three groups (70%, 80%, and self-regulated) with LSD post hoc test to detect any significant differences. Furthermore, to determine the effect of patterns of walking, the structured groups were combined and compared with the unstructured group. The independent t-test was utilized to determine the differences between the two patterns of walking with significant difference was set at p < 0.05. Results: After 10 weeks of study, the findings of the speed of walking showed that Group A and Group B significantly decrease in body weight (p < 0.05) at post-training when compared to the Control. However, only Group B showed significant reduction in body mass index (BMI), waist and hip circumference, waist to hip ratio (WHR), and percent body fat (p < 0.05) at post-training. All study groups exhibited a significant reduction in resting heart rate at post-training (p < 0.05). Group A showed significant decreased in resting systolic and diastolic blood pressure (p < 0.05) while Control exhibited significant reduction in resting systolic blood pressure and peak diastolic blood pressure (p < 0.05) at post-training. No change in blood pressure was observed in Group B. After 10 weeks of training, Group A and Group B exhibited significant increase in VO2 peak at post-training when compared to Control (p < 0.05). All groups showed significant improvement in ventilator threshold, maximal treadmill speed and treadmill time (p < 0.05) at post-training. In terms of CHD risk profiles, Group B showed a significant reduction in total cholesterol, triglycerides, LDL-Cholesterol, and CHOL/HDL ratio (p < 0.05) at post-training. No improvement in these parameters were observed in Group A and Control. When the change of these parameters were compared between groups, Group A and Group B exhibited significant increase VO2 peak and ventilator threshold and significant decrease in total cholesterol and triglycerides (p < 0.05) when compared to Control. The improvement in these parameters were more pronounced in Group B. After 10 weeks of study, the findings of the patterns of walking showed that the structured pattern of walking significantly increase in VO2 peak and ventilator threshold and significantly decrease in waist to hip ratio (WHR) and total cholesterol (p < 0.05) when compared to unstructured pattern of walking. Conclusion: The speed of walking at 70% and 80% of maximal walking speed and the structured pattern of walking improves aerobic capacity, ventilator threshold, and modifies CHD risk profiles in terms of waist to hip ratio, total cholesterol, triglycerides, LDL-Cholesterol, and CHOL/HDL ratio. Walking at optimal speed and in a structured setting results in physiological improvement.