# High Intensity Interval Training Improves Glycaemic Control and Pancreatic β Cell Function of Type 2 Diabetes Patients

PMID: 26258597
Journal: PloS one
Published: 2015
Authors: Madsen SM, Thorup AC, Overgaard K, Jeppesen PB

## Question

Does 8 weeks of low-volume cycling HIIT improve glycemic control, pancreatic beta-cell function, body composition, and fitness in inactive type 2 diabetes patients and matched healthy controls?

## Summary

In inactive older adults with type 2 diabetes and matched healthy controls, 8 weeks of supervised low-volume cycling HIIT improved glycemic control and pancreatic beta-cell-function markers in the diabetes group, and reduced abdominal fat in both groups. The protocol used 10 one-minute cycling intervals three times per week after a warm-up, with one-minute recoveries.

## Population

- Inactive type 2 diabetes patients and matched healthy controls
- Sample size: 23
- Age: T2D 56 +/- 2 years; control 52 +/- 2 years
- Sex: Both genders eligible
- Fitness level: Non-active
- Health status: T2D on oral medication and matched healthy controls; insulin use and major disease excluded

## Methodology

- Non-randomized controlled pre-post exercise intervention
- 8 weeks
- Supervised cycle-ergometer training and clinical testing
- Controlled study design.

## Protocol

- Low-volume cycling HIIT.
- Modality: Cycle ergometer.
- Work intervals: 1 minute.
- Recovery: 1 minute recovery by rest or pedaling at minimum resistance.
- Sets or repetitions: 10 intervals.
- Intensity: Individual power output eliciting about 90% HRmax.
- Session duration: About 30 minutes including warm-up and cool-down.
- Frequency: 3 sessions/week.
- Program length: 8 weeks.
- Progression: Power output increased by about 5% halfway through the intervention.
- Matched healthy control HIIT.
- Modality: Cycle ergometer.
- Work intervals: 1 minute.
- Recovery: 1 minute recovery by rest or pedaling at minimum resistance.
- Sets or repetitions: 10 intervals.
- Intensity: Individual power output eliciting about 90% HRmax.
- Session duration: About 30 minutes including warm-up and cool-down.
- Frequency: 3 sessions/week.
- Program length: 8 weeks.
- Progression: Power output increased by about 5% halfway through the intervention.

## Outcomes

### Glycemia
Status: improved
T2D participants improved fasting glucose, 2-hour OGTT endpoint, and HbA1c.

Fasting glucose p=0.01; 2-hour OGTT endpoint p=0.04; HbA1c p=0.04.

### Pancreatic function
Status: improved
HOMA-IR, HOMA beta-cell function, disposition index, and OGTT glucose continuum improved in T2D.

HOMA-IR p=0.03; HOMA beta-cell function p=0.03; disposition index p=0.03; selected OGTT glucose timepoints p=0.03 to p=0.003.

### Abdominal fat
Status: improved
Abdominal fat mass decreased in both T2D and healthy control groups.

T2D p=0.004, -17.84% +/- 5.02; control p=0.02, -9.66% +/- 3.07.

### Fitness
Status: improved
Absolute and relative VO2max and maximal power output improved after training.

### Safety
Status: unclear
The paper reported screening and ECG checks but did not provide explicit adverse-event results for training sessions in the extracted text.

## Practical Insights

- The 10x1-minute cycling structure is a clear low-volume HIIT template.
- For type 2 diabetes, translation requires clinical screening and conservative safety messaging.
- Glycemic claims should be described as promising because the study was small and non-randomized.

## Limitations

- Small sample
- Non-randomized
- No non-exercise type 2 diabetes control
- Clinical exclusions limit generalizability
- No explicit adverse-event reporting in extracted text
- Sample-flow accounting was not fully clear from the extracted sections

## Safety And Adherence

- No explicit exercise adverse events were reported in the extracted text.
- Participants with physical-activity contraindications or ECG perturbations were excluded.
- Resting and post-work ECG showed no signs of ischemia or arrhythmia during VO2max testing in eligible participants.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/26258597/) (pubmed)
- [DOI](https://doi.org/10.1371/journal.pone.0133286) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4530878/) (full text)

## Agent Guidance

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