The effects of interval walking on caloric expenditure
Purpose: As obesity rates continue to rise in physically inactive individuals, modified training methods should be explored to address exercise adherence. The purposes of the proposed studies were to evaluate the effectiveness of interval walking, intermittent interval walking, and self-paced intermittent interval walking on oxygen uptake (⩒O_2) and excess post- exercise oxygen consumption (EPOC). Methods: In Study I and Study II participants completed a 30-min continuous walking protocol at a low-moderate intensity. Each protocol in these studies incorporated the same volume [90 metabolic equivalent-minutes (MET-min)] of exercise. Study I consisted of two interval walking protocols of cycled high-moderate and low-moderate intensities of 30-s work bouts and active recovery bouts of 60 and 120 s and total durations of 24-min-24-s (protocol 1) and 26-min-20-s (protocol 2). Study II consisted of three 10-min intermittent walking bouts of low-moderate intensities, three 8-min-40-s interval walking bouts of 30-s work bouts and active recovery bouts of 120 s, and three 8-min interval walking protocols of 30-s work bouts and active recovery bouts of 60 s. Study III assessed oxygen uptake before, during, and after continuous, intermittent, and intermittent interval walking of a self-regulated moderate RPE range (RPE 12-13), each totaling 30 min. Intermittent walking consisted of three 10-min bouts of walking and intermittent interval walking consisted of cycled 30-s high-moderate:120-s low-moderate intensity walking. Results: Study I: ⩒O_2 during interval walking was higher (p < 0.05) than during continuous walking; however, EPOC differed only between continuous walking and interval walking protocol 1 (p < 0.05). Study II: Compared to continuous walking, intermittent walking and both intermittent interval walking protocols elicited higher (p < 0.05) cumulative ⩒O_2 during exercise, and cumulative total 20-min EPOC values were higher as well (p < 0.05). Study III: Compared to continuous walking, both self-paced intermittent and intermittent interval walking protocols elicited higher cumulative ⩒O_2 during exercise periods and higher cumulative total 20-min EPOC values (all p < 0.05). Conclusion: These results indicate that moderate-intensity interval and intermittent interval walking protocols elicited higher exercise ⩒O_2 and EPOC compared with continuous walking of the same volume (90 MET-min) or duration (30 min).