Intermittent versus continuous walking: Effects on physiological and psychological variables in sedentary employees during a 10-week intervention
Rodriguez-Hernandez, Mynor G.
Type of DegreePhD Dissertation
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Sedentary behavior elevates the risk of developing hypokinetic related diseases and early mortality. Despite known benefits and efforts to promote exercise as preventive medicine, only a small percentage of adults meet exercise recommendations and even a lower number can maintain this lifestyle. This study targeted sedentary employees using two different walking programs promoting self-regulation and self-efficacy, to observe the effect of both interventions on specific physiological and psychological constructs. Sixty-eight sedentary employees, 17 men and 51 women were randomly assigned to one of three groups. The two experimental conditions were time and intensity matched and consisted of: multiple bouts of walking (Age = 46±9 old years, BMI= 30.33±5.79 kg/m2, mean±standard deviation values) and continuous walking (Age = 48±9 old years, BMI= 30.53±6.17 kg/m2). A third group served as the control group (Age = 42±10 old years, BMI= 27.66±5.11 kg/m2). Self-regulation and self-efficacy questionnaires, accelerometry, and VO2 were obtained at baseline, week 6, and week 11. Glycated hemoglobin (HbA1c) and body were obtained at baseline and week 11. Daily walking was measured via a wrist worn accelerometer (MOVband). Mixed-design ANOVA analyses showed that the continuous group improved significantly overall in self-regulation and its sub-scales from pre-test to 6 weeks and to week 11 (p<0.05). Self-efficacy decreased significantly from pre-test to week 6 (p=0.047) and to week 11 (p=0.008) for all groups. Moderate intensity physical activity increased significantly from pre-test to week 6 (p=0.016), then significantly reduced from week 6 to week 11 (p=0.028). The continuous walking group significantly increased moves from pre-test to week 6 (p=0.033), and had a significant higher percentage of change compared to the control group (p<0.05). There were no changes in VO2max (p>0.05) for all three groups. Glycated hemoglobin (HbA1c) was reduced significantly in the continuous group (p<0.05) with a large effect size (n2=0.297). The intermittent walking group increased lean mass significantly (p<0.001). Fat mass decreased, body weight and fat percentage decreased significantly for all three groups (p<0.05). For sedentary employees, continuous or intermittent walking activity produce similar benefits on body weight, fat mass, and body fat. Meanwhile, intermittent walking allowed sedentary employees to increase lean mass and fat free mass. Intermittent walking could provide at least similar benefits on body composition compared to a continuous walking program. Continuous walking activity seems to be a better approach to improve self-regulatory skills, physical activity and HbA1c in sedentary employees; it may provide a more feasible approach to prescribing exercise in sedentary office employees to reduce the risk of sedentary behavior. In future research, to improve aerobic fitness in this population, walking intensity should be constantly monitored.
- Final Dissertation Mynor Rodriguez-Hernandez.pdf