Introduction Obesity treatment guidelines suggest moderate-intensity continuous training (MICT), but the patient’s compliance to this indication remains low. High-intensity interval training (HIIT) is a time sparing training mode whose metabolic effects are not clear. This study aimed to determine whether a 12-week HIIT was more effective than MICT for weight loss in obese adults.
Methods 44 obese subjects were randomised and trained with isoenergetic treadmill exercises for 12 weeks: MICT (60% of maximal oxygen peak, VO2peak) or HIIT (3–7 repetition of 3 min 100% of VO2peak interspersed by 1.5 min 50% of VO2peak). The primary outcome was a change in body weight; the secondary outcomes were changes in body composition, blood pressure, lipid profile, glycaemia, insulin and VO2peak.
Results 32 subjects (53% male, mean age: 38.5 years, mean body mass index: 35.5 kg/m2) completed the trial. MICT and HIIT showed comparable effect within groups in weight loss (−6.0 kg (−9.0 kg to −3.0 kg) vs −5.7 kg (−8.3 kg to −3.1 kg)), changes in fat mass (−2.9% (−4.4% to −1.4%) vs −3.6% (−5.9% to −1.2%)), fat free mass (−5.3% (−7.8% to −2.8%) vs −5.5% (−8.3% to −2.6%)), diastolic blood pressure (−5.5 mm Hg (−10.6 mm Hg to −0.3 mm Hg) vs −5.8 mm Hg (−11.3 mm Hg to −0.3 mm Hg)) and low-density lipoprotein cholesterol (−16.4 mg/dL (−30.8 mg/dL to −2.0 mg/dL) vs −14.7 mg/dL (−25.6 mg/dL to −3.8 mg/dL)). There was a significant change between groups in VO2peak (HIIT: +461.6 mL (329.3‒593.8 mL); MICT: +170.5 mL (86.7–254.4 mL); p<0001) and duration of sessions (HIIT: 35.0 min (31.7 ‒35.6 min); MICT: 46.5 min (40.2‒48.3 min); p<0.001). No significant changes in systolic blood pressure, high-density lipoprotein cholesterol, triglycerides, glycaemia or plasma insulin were observed.
Conclusions In healthy adults with obesity, HIIT compared with MICT induced similar weight loss and cardiovascular risk factors improvement but resulted in a larger increase in cardiorespiratory fitness over a shorter period.
- aerobic fitness
- body composition
Data availability statement
Data are available upon reasonable request.
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AD and JMS are joint first authors.
Contributors Our work is a product of the intellectual environment of the whole team. All members have contributed in various degrees to its birth. Conception and design of the study: AP, AD and SL. Acquisition of data: JMS, AP, AD, EC, FDV and FV. Data analysis and interpretation, and drafting of the article: AP and AD. Critical revision of the article: JMS, EC, FDV, FV, SL, EDN and GZ. All authors read and approved the final manuscript.
Funding The study was supported by the University of Udine and University of Ferrara research funds.
Competing interests None declared.
Patient and public involvement Patients and/or the public were not involved in the design, or conduct, or reporting, or dissemination plans of this research.
Provenance and peer review Not commissioned; internally peer reviewed.