Low-volume combined aerobic and resistance high-intensity interval training in type 2 diabetes: a randomised controlled trial
Question
Does low-volume combined aerobic and resistance HIIT improve glycaemic control in people with type 2 diabetes compared with waitlist control, and how does it compare with guideline-based combined moderate-intensity continuous training over supervised and self-directed phases?
Summary
In low-active adults with type 2 diabetes, 8 weeks of closely supervised low-volume combined aerobic and resistance HIIT improved HbA1c, body composition, exercise capacity, and several fitness measures compared with a waitlist control. The HIIT program required much less weekly time than the moderate-intensity guideline-based comparator, and short-term results were broadly similar. After supervision ended, adherence fell and most improvements were not maintained at 12 months.
Methodology
- Low-active adults with physician-confirmed type 2 diabetes and HbA1c at least 6.0%.
- 69 participants.
- Combined aerobic and resistance HIIT.
- Work intervals: 1 x 4 minutes aerobic at 85%-95% HRpeak, followed by 8 x 1 minute resistance intervals at RPE >=17.
- Recovery: 1 minute rest after aerobic interval and 1 minute rest between resistance intervals.
- Intensity: Aerobic 85%-95% HRpeak; resistance RPE >=17 on Borg 6-20 scale.
- 26 minutes.
- 3 sessions per week on non-consecutive days.
- 8 weeks supervised plus 10 months self-directed.
- Single-centre prospective randomized waitlist-controlled trial with an 8-week supervised phase and a 10-month self-directed phase.
- HbA1c, Body composition, Exercise capacity and VO2peak, and Exercise adherence were tracked.
Outcomes
HbA1c at week 8
Compared with control, HbA1c decreased in both C-HIIT and C-MICT.
C-HIIT adjusted mean difference -0.7% (95% CI -1.3 to -0.2; p=0.014); C-MICT -1.2% (95% CI -1.9 to -0.6; p=0.001).
Body composition at week 8
C-HIIT and C-MICT reduced fat mass and increased lean mass versus control.
Fat mass adjusted mean difference versus control: C-HIIT -1.9 kg (95% CI -3.1 to -0.6; p=0.005), C-MICT -1.5 kg (95% CI -2.6 to -0.4; p=0.007). Lean mass: C-HIIT +1.5 kg (95% CI 0.8 to 2.3; p<0.001), C-MICT +0.9 kg (95% CI 0.1 to 1.7; p=0.034).
Exercise capacity at week 8
Time on exercise test improved versus control in both exercise groups and improved more with C-HIIT than C-MICT.
Adjusted mean difference versus control: C-HIIT +124 s (95% CI 77 to 171; p<0.001), C-MICT +49 s (95% CI 5 to 93; p=0.028); C-HIIT versus C-MICT +54 s (95% CI 10 to 99; p=0.018).
Month 12 maintenance
After 10 months self-directed exercise, adherence was low and most measures returned to baseline.
C-HIIT self-directed session completion 40.6 +/- 25.6% and intensity adherence 67.1 +/- 34.6%; C-MICT session completion 60.6 +/- 27.5% and intensity adherence 79.8 +/- 20.9%.
Insights
- A 26-minute combined aerobic-resistance HIIT session with 12 minutes of high-intensity work can improve short-term glycaemic and fitness outcomes in supervised type 2 diabetes settings.
- The supervision and monitoring context is central to interpreting both effectiveness and safety.
- Time-efficient programming alone did not solve long-term adherence after the intervention became self-directed.
- Consumer-facing recommendations for type 2 diabetes should include medical screening and careful intensity monitoring.
Limitations
- Month-12 findings were affected by low self-directed adherence.
- The study was not powered for a direct non-inferiority comparison of C-HIIT and C-MICT.
- Participants were a screened clinical population and trained under professional supervision.
- Some detailed eligibility information was in supplemental material and was not extracted here.
Safety
- Participants were excluded for ACSM absolute contraindications to exercise.
- Supervised training used heart-rate and RPE monitoring and a maximum staff-to-participant ratio of 1:2.
- The main article did not report specific exercise-related adverse events.