# Low-volume high-intensity interval training improves cardiometabolic health, work ability and well-being in severely obese individuals: a randomized-controlled trial sub-study

PMID: 33160382
Journal: Journal of translational medicine
Published: 2020 Nov 7
Authors: Reljic D, Frenk F, Herrmann HJ, Neurath MF, Zopf Y

## Question

Does low-volume HIIT improve cardiometabolic health, work ability, and well-being in severely obese sedentary employees compared with nutritional counseling alone?

## Summary

In obese employees with additional cardiometabolic risk factors, 12 weeks of very low-volume supervised cycling HIIT plus nutrition counseling improved VO2max, exercise performance, waist circumference, blood pressure, work ability, and well-being compared with a nutrition-counseling control group. The protocol took only 14 minutes per session, had high attendance and enjoyment, and reported no adverse events.

## Population

- Sedentary employed adults with obesity and cardiometabolic risk
- Sample size: 49
- Age: About 49 years
- Sex: Mixed men and women
- Fitness level: Sedentary; VO2max about 22 mL/kg/min
- Health status: Obesity plus at least two cardiometabolic abnormalities

## Methodology

- Randomized controlled trial sub-study
- 12 weeks
- Controlled study design.

## Protocol

- Low-volume HIIT.
- Modality: Cycle ergometer.
- Work intervals: 1 min at 80%-95% HRmax.
- Recovery: 1 min low-intensity recovery.
- Sets or repetitions: 5.
- Intensity: 80%-95% HRmax; achieved peak interval HR 94.5 +/- 4.0% HRmax.
- Session duration: 14 min.
- Frequency: 2 sessions/week.
- Program length: 12 weeks.
- Progression: Adjust cadence and resistance to reach individualized target HR.
- Control.
- Modality: No structured exercise.
- Program length: 12 weeks.
- Progression: Nutritional counseling only.

## Outcomes

### VO2max
Status: no clear change
HIIT increased absolute and relative VO2max while control declined or did not improve.

### Waist
Status: improved
Waist circumference decreased significantly only in HIIT.

### Blood pressure
Status: improved
Systolic and diastolic blood pressure improved more with HIIT.

### Lipids/glucose
Status: no clear change
Glucose, triglycerides, cholesterol fractions, and LDL/HDL ratio did not show meaningful intervention effects.

### Safety
Status: unclear
No adverse events occurred and enjoyment was high.

## Practical Insights

- A 14-minute, twice-weekly cycling HIIT format can be enough to improve fitness in sedentary adults with obesity when intensity is verified.
- Non-weight-bearing modalities are a practical safety and tolerability choice for higher-BMI users.
- Enjoyment and adherence can be high even in high-risk obesity samples when sessions are brief and supervised.

## Limitations

- Sub-study of a larger trial
- Non-probability sampling may limit generalization
- No long-term adherence or efficacy data
- Supervised cycling setting limits home translation

## Safety And Adherence

- No adverse events occurred at any time point during training sessions.
- Authors recommend pre-participation screening for individuals at increased cardiometabolic risk.
- Authors suggest non-weight-bearing cycling may be better tolerated than running/walking in severe obesity.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/33160382/) (pubmed)
- [DOI](https://doi.org/10.1186/s12967-020-02592-6) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC7648946/) (full text)

## Agent Guidance

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