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

PMID: 28435687
Journal: BMC obesity
Published: 2017
Authors: Kelly BM, Xenophontos S, King JA, Nimmo MA

## Question

Do 4 or 6 sessions of low-volume cycle HIIT over 2 weeks improve aerobic capacity, glucose metabolism, body composition, blood pressure, or inflammatory profile in overweight and obese men?

## Summary

In a small pilot study of 18 overweight or obese men, 4 or 6 low-volume cycle HIIT sessions over 2 weeks did not significantly improve fasting glucose, insulin sensitivity, aerobic capacity, body composition, blood pressure, or inflammatory markers. The exact workout structure is useful for low-volume HIIT design, but the short duration and no-control design limit conclusions.

## Population

- Overweight or obese adult men
- Sample size: 18
- Age: Not clearly summarized in extracted text
- Sex: Male
- Fitness level: Low activity; exercised less than twice per week
- Health status: Overweight or obese but otherwise healthy; impaired fasting glucose and diabetes excluded

## Methodology

- Small pilot intervention trial comparing two HIIT doses
- 2 weeks
- University research exercise-testing setting
- Controlled study design.

## Protocol

- Six-session low-volume HIIT.
- Modality: Cycle ergometer.
- Work intervals: 1 min at resistance intended to elicit about 90% HRpeak.
- Recovery: 1 min active recovery at 50 W.
- Sets or repetitions: 10 intervals.
- Intensity: About 90% HRpeak; cadence 80-100 rpm during work intervals.
- Session duration: About 25 min including warm-up and cool-down.
- Frequency: 3 sessions/week for 2 weeks.
- Program length: 2 weeks.
- Progression: No progression described.
- Four-session low-volume HIIT.
- Modality: Cycle ergometer.
- Work intervals: 1 min at resistance intended to elicit about 90% HRpeak.
- Recovery: 1 min active recovery at 50 W.
- Sets or repetitions: 10 intervals.
- Intensity: About 90% HRpeak; cadence 80-100 rpm during work intervals.
- Session duration: About 25 min including warm-up and cool-down.
- Frequency: 2 sessions/week for 2 weeks.
- Program length: 2 weeks.
- Progression: No progression described.

## Outcomes

### Fasting glucose
Status: no clear change
Neither 4 nor 6 sessions significantly changed fasting glucose.

No significant within-group change reported; p>0.05.

### Insulin sensitivity
Status: no clear change
Fasting insulin, OGTT AUC measures, and Matsuda insulin sensitivity did not significantly change.

All glycemic and insulin sensitivity outcomes p>0.05.

### VO2peak
Status: no clear change
VO2peak did not significantly improve after either dose.

Group 1 relative VO2peak 35.6 +/- 5.4 to 38.5 +/- 5.4 ml/kg/min, p=0.135; group 2 30.4 +/- 4.2 to 30.5 +/- 3.9 ml/kg/min, p=0.960.

### Body composition
Status: no clear change
Body mass, BMI, waist and hip circumferences, and DEXA measures did not significantly change.

No body-composition or anthropometric change reached p<0.05.

### Inflammation
Status: no clear change
Measured inflammatory proteins did not significantly change.

Adiponectin, IL-10, TNF-alpha, IL-6, sIL-6R, CRP, and MCP-1 all p>0.05.

## Practical Insights

- A 10 x 1-min, 1:1 work-recovery cycling protocol is reproducible and time efficient.
- Two weeks of 4-6 sessions should not be presented as sufficient evidence for improving cardiometabolic or inflammatory markers.
- Baseline risk level matters: relatively healthy markers may limit observable change.

## Limitations

- Small pilot sample
- Male-only sample
- No nonexercise control group
- Very short 2-week intervention
- Participants had relatively healthy baseline glucose, insulin, and inflammatory profiles
- Session completion and adverse-event reporting were not clearly extracted

## Safety And Adherence

- Participants were informed of possible risks and discomforts.
- Adverse events were not reported in the extracted text.
- Eligibility excluded smokers, impaired fasting glucose, diabetes, and BMI >= 40 kg/m2.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/28435687/) (pubmed)
- [DOI](https://doi.org/10.1186/s40608-017-0151-7) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5395873/) (full text)

## Agent Guidance

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