Integrating high‐intensity interval training into the workplace: The Work‐HIIT pilot RCT

The purpose of this study was to assess the feasibility and preliminary efficacy of a high‐intensity interval training (HIIT) intervention integrated into the workplace on physical and mental health outcomes in a sample of adults. The Work‐HIIT intervention was evaluated at the University of Newcastle (March‐July 2019). University employees (18+ years) who self‐identified as predominantly sedentary at work (n = 47, 43.0 ± 10.7 years; 41 female) were recruited, screened, and randomized after baseline assessments into Work‐HIIT (n = 24) or wait‐list control (n = 23) conditions. Participants were asked to attend 2‐3 researcher‐facilitated HIIT sessions/week (weeks 1‐8). Sessions included a 2‐minute gross‐motor warm‐up, followed by various combinations of aerobic and muscular fitness exercises lasting 8 minutes (using 30:30 second work: rest intervals). Program feasibility was assessed using measures of satisfaction, compliance, adherence, fidelity, and retention. Physiological and psychological outcomes were measured at baseline and 9 weeks. Feasibility data were investigated using descriptive statistics and efficacy outcomes determined using linear mixed models and Cohen's d effect sizes. Participant ratings showed high levels of satisfaction (4.6/5); 71% of participants attended ≥2 sessions/wk and averaged 85.9% HR max across all sessions (including rest and work intervals). Small‐to‐medium positive effects resulted for cardiorespiratory fitness [+2.9 laps, 95% CI (−4.19‐10.14); d  = 0.34] and work productivity [+0.26, d  = 0.47]. Large positive effects resulted for muscular fitness [push‐ups +3.5, d  = 0.95; standing jump +10.1 cm, d  = 1.12]; HIIT self‐efficacy [+16.53, d  = 1.57]; sleep [weekday +0.76 hours, d  = 1.05]; and autonomous motivation [+0.23, d  = 0.76]. This study supports the feasibility and preliminary efficacy of facilitator‐led Work‐HIIT as a time‐efficient, enjoyable, and convenient workplace exercise option for adults.