Acute Metabolic and Enjoyment Responses of Three Walking Protocols

Jermaine B Mitchell,Phillip Bishop,Jonathan E Wingo,Robert L Herron,Mark T Richardson

doi:10.12691/jpar-2-1-5

Abstract

Encouraging physical activity is a key component of public health. The purpose of this study was to test the hypothesis that interval walking would produce higher oxygen uptake (VO2) and similar enjoyment responses during and following exercise compared to continuous walking. Ten healthy adults (4 women, 6 men; mean age = 24 ± 5 years) completed the following 3 walking bouts in counterbalanced order and equated for total volume (90 MET·min): 1) 30 min of low-moderate continuous walking (3 METs; ~ 4.8 km/h), 2) 24 min and 24 s of interval walking (IW1) with cycles of 30 s:60 s of high-moderate (5 METs; ~ 6.4 km/h):low-moderate intensities, and 3) 26 min and 20 s of interval walking (IW2) with cycles of 30 s:120 s of high-moderate:low-moderate intensities. Accumulated O2 uptake during exercise was higher during IW2 (28,232 ± 2,782 mL) compared to IW1 (26,561 ± 2,685 mL; p = 0.03) and continuous walking (24,500 ± 2,427 mL; p = 0.001), and higher during IW1 than during continuous walking (p = 0.001). EPOC over 20 min was higher after IW1 (1,268 ± 117 mL O2) compared to continuous walking (892 ± 73 mL; p = 0.04); the 2 interval walking protocols were not different (IW2: 1,174 ± 178 mL; p > 0.05). Exercise enjoyment before, during, and after exercise did not differ among the walking protocols (all p > 0.05). Interval walking elicited greater VO2 and EPOC in shorter total durations of exercise compared to continuous walking of a similar enjoyment and volume.

Highlights

Physical inactivity in adults today is a tremendous public health challenge that contributes to excess fat accumulation and an increase in the prevalence and incidence of chronic disease, e.g., type II diabetes, cardiovascular disease, hyperglycemia, and obesity [22]
In support of our hypothesis, the primary findings were that the interval walking protocols—despite being comprised of shorter durations than continuous walking (IW1: 19% shorter duration; IW2: 11% shorter duration)—resulted in greater accumulated O2 uptake during exercise (IW1: 8%; IW2: 13%) and greater EPOC (IW1: 30%; IW2: 24%)
The more intense, moderate intensity interval walking protocols produced similar exercise enjoyment and rating of perceived exertion (RPE) as continuous walking. These findings are similar to a previous field experiment conducted by our laboratory that investigated the self-reported enjoyment responses of 3 self-selected intensity walking protocols [1 continuous walking protocol at a low-moderate intensity (RPE-12) and 2 interval walking protocols with work bouts set at 30s high-moderate (RPE-13): 60 s low-moderate and 30s high-moderate: 120s lowmoderate intensities] of constant duration (20 min) in adult females

Summary

Introduction

Physical inactivity in adults today is a tremendous public health challenge that contributes to excess fat accumulation and an increase in the prevalence and incidence of chronic disease, e.g., type II diabetes, cardiovascular disease, hyperglycemia, and obesity [22]. Interval training has been shown to provide greater or similar benefits to traditional continuous training in a shorter time [5,9,18] and may represent a time-efficient strategy to increase physical activity [16]. 2max) and increased muscle glycogen and maximal activity of citrate synthase [8,9] associated with interval training compared to traditional continuous training, regardless of age, sex, or health status [8,9,18,24,31]. Selfridge [31] noted high intensity interval training to be more effective for increasing maximum exercise capacity, improving blood pressure, reducing body fat, and raising HDL-C than continuous moderate exercise. Negative post-exercise affect responses reduces exercise adherence and have been linked to high intensity interval training [27,37,38]

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