# Low-volume combined aerobic and resistance high-intensity interval training in type 2 diabetes: a randomised controlled trial PMID: 39381412 Journal: BMJ Open Sport & Exercise Medicine Published: 2024 Authors: Gajanand T, Cox ER, Keating SE, Brown WJ, Hordern MD, Burton NW, Chachay VS, Gomersall SR, Fassett RG, Coombes JS ## 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. ## Population - Low-active adults with physician-confirmed type 2 diabetes and HbA1c at least 6.0%. - Sample size: 69 - Age: Mean 59.5 +/- 8.8 years; eligible age 18-80 years. - Sex: 42 male, 27 female. - Fitness level: Low-active; mean baseline VO2peak about 23-25 mL/kg/min across groups. - Health status: Type 2 diabetes; most participants used oral antihyperglycaemic medication and about one-fifth used insulin. ## Methodology - Single-centre prospective randomized waitlist-controlled trial with an 8-week supervised phase and a 10-month self-directed phase. - 8 weeks supervised training plus 10 months self-directed exercise; outcomes at baseline, week 8, and month 12. - The University of Queensland; supervised exercise sessions led by accredited exercise physiologists, followed by self-directed exercise with optional monthly supervised sessions. - Randomized and controlled study design. ## Protocol - C-HIIT. - Modality: 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. - Sets or repetitions: 1 aerobic interval plus 8 resistance intervals; resistance work used as many correct repetitions as possible, at least 5 and aiming for 10-25. - Intensity: Aerobic 85%-95% HRpeak; resistance RPE >=17 on Borg 6-20 scale. - Session duration: 26 minutes. - Frequency: 3 sessions per week on non-consecutive days. - Program length: 8 weeks supervised plus 10 months self-directed. - Progression: Individualized resistance progression using RPE and repetitions; workloads adjusted by exercise physiologists. - C-MICT and waitlist control. - Modality: Combined moderate-intensity aerobic and resistance training, plus waitlist usual care control. - Work intervals: Continuous aerobic exercise; no high-intensity intervals. - Recovery: Resistance sets separated by 1-minute rest in combined sessions. - Sets or repetitions: Two combined sessions per week used 2 sets of 10 repetitions for each resistance exercise; two aerobic-only sessions per week. - Intensity: Aerobic 55%-69% HRpeak; resistance RPE 11-13. - Session duration: 52.5 minutes per session. - Frequency: 4 sessions per week. - Program length: 8 weeks supervised plus 10 months self-directed for exercise groups; waitlist control usual care for 8 weeks before re-randomization. - Progression: Moderate-intensity exercise based on current type 2 diabetes recommendations; self-directed continuation after phase 1. ## Outcomes ### HbA1c at week 8 Status: improved 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 Status: improved 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 Status: improved 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 Status: mixed 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%. ## Practical 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 And Adherence - 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. ## Original Sources - [PubMed](https://pubmed.ncbi.nlm.nih.gov/39381412/) (pubmed) - [DOI](https://doi.org/10.1136/bmjsem-2024-002046) (doi) - [PMC full text](https://www.ncbi.nlm.nih.gov/pmc/articles/PMC11459303/) (full text) ## Agent Guidance Preserve the paper-level scope of this note. Do not generalize beyond the population, protocol, measured outcomes, and limitations above.