# Intensive lifestyle intervention including high-intensity interval training program improves insulin resistance and fasting plasma glucose in obese patients

PMID: 26844086
Journal: Preventive medicine reports
Published: 2015
Authors: Marquis-Gravel G, Hayami D, Juneau M, Nigam A, Guilbeault V, Latour É, Gayda M

## Question

Does a 9-month intensive lifestyle program including supervised HIIT, resistance training, and Mediterranean diet counseling improve glycemic control and insulin resistance in obese patients?

## Summary

In a retrospective cohort of 72 obese adults who completed a 9-month lifestyle program, supervised HIIT plus resistance training and Mediterranean diet counseling improved fasting glucose, fasting insulin, and HOMA-IR, especially in those who were insulin resistant at baseline. Because there was no control group and non-completers were excluded, the evidence is supportive but not causal.

## Population

- Seventy-two obese adults who completed a clinical lifestyle program; 54 women and 18 men.
- Sample size: 72
- Age: 53 +/- 9 years
- Sex: 54 women, 18 men
- Fitness level: Obese clinical participants; VO2peak 8.6 +/- 1.6 METs
- Health status: Obesity; 10% diabetes, 31% hypertension, 36% dyslipidemia; 57% insulin resistant by HOMA-IR >=2.6

## Methodology

- Retrospective clinical cohort
- 9 months
- Montreal Heart Institute EPIC center lifestyle program

## Protocol

- Lifestyle program with HIIT and resistance training.
- Modality: Cycle ergometer HIIT plus resistance circuit and Mediterranean diet counseling.
- Work intervals: 15-30 s.
- Recovery: 15-30 s passive recovery.
- Sets or repetitions: Two 10-min sets of repeated intervals, separated by 4-min passive recovery.
- Intensity: 80% maximal aerobic power; target Borg RPE 15.
- Session duration: 60 min total: 34 min HIIT plus 20 min resistance training.
- Frequency: 2-3 supervised sessions/week; encouraged 1-2 additional unsupervised moderate sessions/week.
- Program length: 9 months.
- Progression: Individualized from baseline treadmill maximal test and clinical supervision.

## Outcomes

### Fasting glucose
Status: improved
Fasting plasma glucose decreased after the program.

5.5 +/- 0.9 to 5.2 +/- 0.6 mmol/L; p<0.0001

### Fasting insulin
Status: improved
Fasting insulin decreased after the program.

98 +/- 57 to 82 +/- 43 pmol/L; p=0.003

### HOMA-IR
Status: improved
Insulin resistance improved, especially among participants who were insulin resistant at baseline.

All subjects 3.6 +/- 2.5 to 2.8 +/- 1.6, p=0.0008; insulin-resistant subgroup 5.1 to 3.5

### HbA1c
Status: no clear change
HbA1c did not change significantly.

5.72 to 5.69%; p=0.448

## Practical Insights

- A long, supervised lifestyle program combining HIIT, resistance training, and diet counseling can improve fasting glycemic markers in obese adults.
- Benefits were strongest for those with baseline insulin resistance.
- Because diet and exercise were bundled, the HIIT-specific contribution cannot be isolated.

## Limitations

- Retrospective design.
- No comparator group.
- Only completers with final data were analyzed, creating selection bias.
- Mediterranean diet adherence data were unavailable.
- HOMA-IR is a surrogate and OGTT was not used.
- Participants paid for and self-selected into a clinical program.

## Safety And Adherence

- Adverse events were not reported.
- Exercise was supervised by kinesiologists in a clinical prevention center.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/26844086/) (pubmed)
- [DOI](https://doi.org/10.1016/j.pmedr.2015.04.015) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4721397/) (full text)

## Agent Guidance

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