# Effectiveness of high-intensity interval training for weight loss in adults with obesity: a randomised controlled non-inferiority trial

PMID: 34367654
Journal: BMJ open sport & exercise medicine
Published: 2021
Authors: D'Amuri A, Sanz JM, Capatti E, Di Vece F, Vaccari F, Lazzer S, Zuliani G, Dalla Nora E, Passaro A

## Question

Is 12-week treadmill HIIT non-inferior to moderate-intensity continuous training for weight loss in adults with obesity?

## Summary

In healthy adults with obesity, 12 weeks of supervised treadmill HIIT plus a hypocaloric diet produced weight loss and body-composition changes similar to moderate continuous treadmill training. HIIT sessions were shorter and improved VO2peak more, while dropout rate and adverse-event reporting were similar.

## Population

- Healthy inactive adults with obesity
- Sample size: 32
- Age: Mean 38.5 years
- Sex: 53% male
- Fitness level: Inactive at baseline
- Health status: Obesity without major comorbidities

## Methodology

- Randomized single-blind single-center parallel-group non-inferiority trial
- 12 weeks
- Controlled study design.

## Protocol

- HIIT.
- Modality: Treadmill.
- Work intervals: 3 min at 100% VO2peak.
- Recovery: 1.5 min at 50% VO2peak.
- Sets or repetitions: 3-7 repetitions.
- Intensity: 100% VO2peak work, 50% VO2peak recovery.
- Session duration: Median 35.0 min including warm-up/cool-down.
- Frequency: 3 sessions/week.
- Program length: 12 weeks.
- Progression: Monthly aerobic testing adjusted speed/incline and session prescription to remain isoenergetic.
- MICT.
- Modality: Treadmill.
- Work intervals: Continuous exercise.
- Recovery: Not applicable.
- Sets or repetitions: One continuous bout.
- Intensity: Heart rate corresponding to 60% baseline VO2peak.
- Session duration: Median 46.5 min.
- Frequency: 3 sessions/week.
- Program length: 12 weeks.
- Progression: Adjusted to maintain isoenergetic target of 20 kJ/kg fat-free mass.

## Outcomes

### Weight
Status: unclear
Both groups lost similar weight.

### VO2peak
Status: improved
HIIT increased VO2peak more than MICT.

### Session time
Status: unclear
HIIT sessions were shorter.

### Glucose and insulin
Status: no clear change
Triglycerides, plasma glucose, insulin, and HOMA-IR did not change significantly.

### Safety
Status: unclear
No adverse events occurred in either group.

## Practical Insights

- In adults with obesity and minimal comorbidities, treadmill HIIT can deliver similar short-term weight loss to MICT with less session time when paired with diet.
- Fitness improvements may be a stronger differentiator for HIIT than scale weight.
- Claims about weight loss should note the hypocaloric diet co-intervention.

## Limitations

- Small completer sample
- Underpowered for sex-specific and some secondary effects
- BIA is less accurate than gold-standard body-composition methods
- No long-term adherence assessment
- Participants had obesity but minimal comorbidities

## Safety And Adherence

- No adverse events occurred in either group.
- Twelve randomized participants dropped out; seven for inadequate workout adherence and five withdrew consent.
- Exercise testing was medically supervised.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/34367654/) (pubmed)
- [DOI](https://doi.org/10.1136/bmjsem-2020-001021) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC8292807/) (full text)

## Agent Guidance

Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.