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
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.
Methodology
- 27 physically inactive overweight or obese adults, including women with PCOS.
- 27 participants.
- Cycle ergometer.
- Work intervals: 1 min.
- Recovery: 1 min active recovery at 50 W.
- Intensity: 100% Wmax during work intervals.
- 24 min.
- One acute session.
- Single exercise day.
- Randomized parallel-group acute exercise study with rest-day comparator and continuous glucose monitoring
- 24 h glucose, Postprandial glucose, and Redox markers were tracked.
Outcomes
24 h glucose
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
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
MAGE, SD, and percent CV were not significantly changed.
Trial day and group p>0.05.
Redox
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.
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
- No adverse events or injuries were reported.
- Participants were screened for medical risk and activity-limiting conditions.