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High-Intensity Interval or Continuous Moderate Exercise

A 24-Week Pilot Trial

LOCKE, SEAN R.1; BOURNE, JESSICA E.1; BEAUCHAMP, MARK R.2; LITTLE, JONATHAN P.1; BARRY, JULIANNE1; SINGER, JOEL3; JUNG, MARY E.1

Medicine & Science in Sports & Exercise: October 2018 - Volume 50 - Issue 10 - p 2067–2075
doi: 10.1249/MSS.0000000000001668
APPLIED SCIENCES
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Purpose High-intensity interval training (HIIT) may lead to superior cardiometabolic improvements when compared with moderate-intensity continuous training (MICT). However, adherence to HIIT requires examination. The purpose of this pilot study was to examine moderate-to-vigorous physical activity (MVPA) adherence 24 wk after a brief counseling intervention combined with either HIIT or MICT.

Methods Individuals at high risk of type 2 diabetes (T2D) were randomized to HIIT (n = 15) or MICT (n = 17) and completed 10 exercise sessions accompanied by a brief 10-min counseling intervention over a 2-wk period. Objectively measured purposeful MVPA (accelerometry) and cardiorespiratory fitness (V˙O2peak) were assessed at baseline and 24 wk postintervention. Self-regulatory efficacy and task self-efficacy were examined at baseline, postintervention, and 24 wk postintervention. Using an intention-to-treat analysis, change scores were calculated for HIIT and MICT and compared between groups.

Results Individuals assigned to HIIT increased their MVPA by 53 min (Cohen’s d = 1.52) at 24 wk compared with 19 min in MICT. Both HIIT and MICT increased relative V˙O2peak by 2 and 1 mL·kg−1·min−1, respectively. Participants in both groups increased in their self-regulatory and task self-efficacy postintervention, but both groups demonstrated similar decline at 24 wk.

Conclusion This pilot intervention was successful in increasing, and maintaining, free-living MVPA over a 24-wk period in individuals at high risk of T2D. Speculation that HIIT is inappropriate or unattainable for overweight individuals at high risk of T2D may be unfounded.

1School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, Kelowna, BC, CANADA;

2School of Kinesiology, University of British Columbia, Vancouver, BC, CANADA; and

3School of Population and Public Health, University of British Columbia, Vancouver, BC, CANADA

Address for correspondence: Mary E. Jung, Ph.D., School of Health and Exercise Sciences, University of British Columbia, Okanagan Campus, 3333 University Way, Kelowna, British Columbia V1V 1V7, Canada; E-mail: mary.jung@ubc.ca.

Submitted for publication January 2018.

Accepted for publication April 2018.

© 2018 American College of Sports Medicine