Evaluating the feasibility and efficacy of a home-based combined high intensity interval and moderate intensity training program for increasing physical activity among low-active adults: A randomized pilot trial

PLOS ONE RESEARCH ARTICLE Evaluating the feasibility and efficacy of a home-based combined high intensity interval and moderate intensity training program for increasing physical activity among low-active adults: A randomized pilot trial Beth A. Lewis ID1*, Katie Schuver ID1, Shira Dunsiger2 a1111111111 a1111111111 a1111111111 a1111111111 a1111111111 1 School of Kinesiology, University of Minnesota, Minneapolis, Minnesota, United States of America, 2 Center for Health Promotion and Health Equity, Brown University, Providence, Rhode Island, United States of America * Abstract OPEN ACCESS Citation: Lewis BA, Schuver K, Dunsiger S (2023) Evaluating the feasibility and efficacy of a homebased combined high intensity interval and moderate intensity training program for increasing physical activity among low-active adults: A randomized pilot trial. PLoS ONE 18(2): e0281985. https://doi.org/10.1371/journal.pone.0281985 Editor: Shibili Nuhmani, Imam Abdulrahman Bin Faisal University, SAUDI ARABIA Received: August 23, 2021 Accepted: February 5, 2023 Published: February 21, 2023 Copyright: © 2023 Lewis et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited. Data Availability Statement: All relevant data are within the paper and its Supporting information files. Funding: The authors received no specific funding for this work. Competing interests: The authors have declared that no competing interests exist. Background High intensity interval training (HIIT), which includes short bursts of high-intensity physical activity (PA) followed by recovery, can increase PA by addressing time barriers and improving PA enjoyment. The purpose of this pilot study was to examine the feasibility and preliminary efficacy of a home-based HIIT intervention on PA. Methods Low active adults (n = 47) were randomly assigned to a home-based HIIT intervention or wait-list control lasting 12 weeks. Participants in the HIIT intervention received motivational phone sessions based on Self-Determination Theory and accessed a website that included workout instructions and videos demonstrating proper form. Results The HIIT intervention appears feasible based on retention, recruitment, adherence to the counseling sessions, follow-up rates, and the consumer satisfaction survey. HIIT participants reported more minutes of vigorous intensity PA at six weeks relative to control (no differences at 12 weeks). HIIT participants reported higher levels of self-efficacy for PA, enjoyment of PA, outcome expectations related to PA, and positive engagement with PA than the control. Conclusions This study provides evidence for feasibility and possible efficacy of a home-based HIIT intervention for vigorous intensity PA; however, additional studies are needed with larger samples sizes to confirm efficacy of home-based HIIT interventions. PLOS ONE | https://doi.org/10.1371/journal.pone.0281985 February 21, 2023 1 / 13 PLOS ONE HIIT for increasing physical activity Trial registration Clinical Trials Number: NCT03479177. Introduction Physical activity (PA) is associated with numerous health benefits including the reduced risk of cardiovascular disease, type 2 diabetes, stroke, depression, anxiety, and sleep problems [1]. It is also associated with improved bone health [2] and cognitive functioning [3]. Consequently, the US Department of Health and Human Services recommend that adults engage in 75–150 minutes of vigorous intensity PA per week or 150–300 minutes of moderate intensity PA per week, and muscle strengthening activities of moderate or greater intensity for two or more days per week [1]. Unfortunately, only 19% of women and 26% of men meet the aerobic and muscle strengthening PA guidelines. Research indicates that vigorous intensity PA may be superior to moderate intensity PA for reducing the risk of chronic diseases such as type 2 diabetes and cardiovascular disease [4, 5]. Specifically, one study found that the CVD mortality hazard ratios were more than two times higher among obese individuals who met the moderate intensity guidelines vs. those who met the vigorous intensity guidelines. Additionally, research indicates that muscle strengthening activities may be particularly important for reducing chronic disease risk [6]. Behavioral interventions are efficacious for increasing PA among low-active and sedentary adults [7]. However, long-term adherence is problematic. Additionally, most behavioral interventions encourage moderate intensity PA but do not target vigorous intensity or muscle strengthening activities [7]. This is a significant limitation given the numerous health benefits related to vigorous intensity and muscle strengthening activities [8]. Recent research has examined the efficacy of High Intensity Interval Training (HIIT) as a strategy to address the limitations of previous traditional PA studies [9–11]. High Intensity Interval Training (HIIT) consists of short bouts of vigorous intensity PA followed by rest or active recovery [12]. HIIT addresses the “lack of time” barrier since it takes less time than moderate intensity PA [13]. Additionally, HIIT is advantageous to traditional vigorous intensity activity since it includes active recovery or rest. Some studies indicate that HIIT may be more enjoyable than moderate intensity, continuous PA [14, 15]; however, others have argued that this is not the case [16]. Biddle and Batterham [17] summarized the arguments for and against promoting HIIT as a viable PA program. Biddle argued that due to the aversive nature of high intensity exercise, HIIT is not a viable public health strategy. However, Batterham argued that this idea is outdated and based on traditional continuous vigorous intensity program rather than interval training. In sum, more research is needed to better understand the viability of HIIT and the effect of HIIT on affective responses (i.e., pleasurable vs. unpleasurable) to PA. A majority of HIIT studies have been conducted in a laboratory, which does not address long-term adherence to PA nor do lab-based studies generalize to real world settings [8]. Studies that have examined home-based HIIT have yielded in mixed results [11, 18, 19]. Major limitations for many of these studies is the lack of focus on strengthening activities, which is inconsistent with PA guidelines, and no or little focus on theory-based behavioral strategies to increase adherence. The purpose of this pilot study was to examine the feasibility and efficacy of a 12-week home-based High Intensity Interval Training (HIIT) program among low-active individuals relative to a wait-list control arm. Self-Determination Theory informed the intervention for PLOS ONE | https://doi.org/10.1371/journal.pone.0281985 February 21, 2023 2 / 13 PLOS ONE HIIT for increasing physical activity (...truncated)