An evaluation of low volume high-intensity intermittent training (HIIT) for health risk reduction in overweight and obese men.

ᅟ: Both sprint interval training (SIT) and high-intensity intermittent training (HIIT) have been described as time-efficient strategies for inducing favourable metabolic and cardiorespiratory adaptations in healthy and diseased participants.

Background: To date, little attention has been given to profiling the potential health benefits of HIIT or modified HIIT training within overweight and obese cohorts with particular focus on inflammation. Within this pilot trial, we tested the hypothesis that 6 sessions of HIIT performed over 2 weeks with 1-2 days' rest would improve aerobic capacity, glucose metabolism and inflammatory profile in an overweight and obese male cohort. Additionally, we profiled the potential health benefits of 4 HIIT sessions performed over the same period.

Methods: 18 overweight or obese males (BMI = 31.2 ± 3.6; V̇O₂ = 30.3 ± 4.4 ml.kg.min^-1) were studied before and 72 h after HIIT. Training sessions consisted of 10 x 1 min intervals at 90% HR_peak separated by 1 min recovery periods. Exercise was performed either 6 (group 1, n = 8) or 4 (group 2, n = 10) times over a 2 week period.

Results: After training no changes were detected from baseline for body composition, aerobic capacity, glucose metabolism or inflammatory profile (p > 0.05) in either group.

Conclusion: Both 6 and 4 sessions of HIIT performed over a 2-week period are ineffective in improving selected health markers within an overweight and obese cohort.

Trial registration: This trial reports data from human participants and was retrospectively registered on 22/02/2017 with the ISRCTN registry, trial number ISRCTN90672085.