# Acute Low-Volume High-Intensity Interval Exercise and Continuous Moderate-Intensity Exercise Elicit a Similar Improvement in 24-h Glycemic Control in Overweight and Obese Adults

PMID: 28119617
Journal: Frontiers in Physiology
Published: 2017
Authors: Parker L, Shaw CS, Banting L, Levinger I, Hill KM, McAinch AJ, Stepto NK

## Question

Does a single low-volume high-intensity interval cycling session improve 24-hour glycemic control and postprandial redox status more than continuous moderate-intensity cycling in inactive overweight and obese adults?

## Summary

Twenty-seven inactive overweight or obese adults were randomized to one acute cycling session after breakfast: low-volume high-intensity intervals or continuous moderate-intensity exercise. Both exercise modes improved 24-hour glucose control similarly, but only moderate continuous exercise attenuated postprandial oxidative-stress markers; low-volume HIIE raised some oxidative-stress markers in the early post-exercise period.

## Population

- 27 physically inactive overweight or obese adults, including women with PCOS.
- Sample size: 27
- Age: LV-HIIE 30 +/- 1 years; CMIE 30 +/- 2 years
- Sex: 17 females and 10 males total; LV-HIIE 9F/5M, CMIE 8F/5M
- Fitness level: Sedentary, no regular moderate-to-high physical activity in previous 3 months
- Health status: Overweight or obese on average; 11 women with PCOS

## Methodology

- Randomized parallel-group acute exercise study with rest-day comparator and continuous glucose monitoring
- Four consecutive experimental days with one acute exercise session
- Laboratory cycling protocol with free-living CGM under standardized diet
- Randomized and controlled study design.

## Protocol

- Low-volume HIIE cycling.
- Modality: Cycle ergometer.
- Work intervals: 1 min.
- Recovery: 1 min active recovery at 50 W.
- Sets or repetitions: 8.
- Intensity: 100% Wmax during work intervals.
- Session duration: 24 min.
- Frequency: One acute session.
- Program length: Single exercise day.
- Progression: None.
- Continuous moderate-intensity exercise.
- Modality: Cycle ergometer.
- Sets or repetitions: Continuous cycling.
- Intensity: 50% Wmax.
- Session duration: 38 +/- 1 min.
- Frequency: One acute session.
- Program length: Single exercise day.
- Progression: None.

## Outcomes

### 24 h glucose
Status: improved
Both LV-HIIE and CMIE similarly reduced 24 h average glucose, AUC, peak glucose, and time above 7 mmol/L.

All exercise-day effects p<0.05 with no LV-HIIE vs CMIE differences p>0.05.

### Dinner glucose
Status: improved
Exercise reduced dinner postprandial glucose measures in both groups.

Dinner 2 h average glucose, peak glucose, AUC, and iAUC all p<0.05.

### Glycemic variability
Status: no clear change
MAGE, SD, and percent CV were not significantly changed.

Trial day and group p>0.05.

### Redox
Status: mixed
CMIE attenuated TBARS and hydrogen peroxide, whereas LV-HIIE did not and showed higher early oxidative-stress response.

CMIE TBARS p<0.01 and hydrogen peroxide p=0.04; LV-HIIE TBARS p=0.34 and hydrogen peroxide p=0.37 in abstract.

## Practical Insights

- A brief 8 x 1 min cycling HIIE session can improve next-day glucose exposure similarly to longer moderate cycling in this sample.
- Immediate post-exercise responses may look different from 24-hour glycemic effects, especially after high-intensity exercise.

## Limitations

- Small sample
- Parallel rather than crossover design
- Participants were not blinded to real-time CGM readings
- Subgroup analyses by sex or PCOS were not possible
- Acute session only

## Safety And Adherence

- No adverse events or injuries were reported.
- Participants were screened for medical risk and activity-limiting conditions.

## Original Sources

- [PubMed](https://pubmed.ncbi.nlm.nih.gov/28119617/) (pubmed)
- [DOI](https://doi.org/10.3389/fphys.2016.00661) (doi)
- [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC5220056/) (full text)

## Agent Guidance

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