Eight weeks of high-intensity combined aerobic and resistance exercise may safely reduce musculoskeletal pain in inactive individuals with type 2 diabetes (T2D), according to the results of a randomized controlled study published in Diabetes Research and Clinical Practice.
Studies have shown high-intensity interval training (HIIT) to be more effective in improving cardiorespiratory fitness and glycemic control in individuals with T2D than moderate-intensity continuous training (MICT), and although a combination of aerobic and resistance training is recommended in T2D, few exercise studies have included both types. With regard to pain management, the analgesic effects of exercise may be intensity-dependent, but the effect of HIIT on chronic pain has not yet been investigated.
To compare the safety and efficacy of low-volume combined aerobic and resistance HIIT and combined aerobic and resistance MICT with that of usual care in inactive individuals with T2D, 32 patients (41% women; mean age, 58.7±9.1 years) with medically diagnosed T2D were randomly assigned to a control group or combined aerobic and resistance MICT or HIIT treatment groups. Individuals with absolute contraindications to exercise were excluded, and those who participated in >150 minutes of moderate physical activity or >75 minutes of vigorous physical activity per week were also excluded.
A total of 26 individuals completed the study. Participants randomly assigned to the exercise groups underwent variations of an 8-week exercise program that combined machine-based, bodyweight, and free-weight exercises with aerobic training. Individuals in the MICT group trained 4 times per week, with 2 sessions that combined moderate-intensity resistance and aerobic training at 55% to 69% of heart rate (HR) peak and 2 sessions that included only aerobic training at the same HR peak. Individuals in the HIIT group trained 3 times per week, with each session consisting of a warm-up and cool down at 50% to 60% HR peak, aerobic exercise at 85% to 95% HR peak, and 1-minute intervals of very-high-exertion resistance training each separated by 1 minute of rest. The HIIT group exercised for a total of 78 minutes per week compared with 210 minutes per week in the MICT group. Participants in the control group continued usual care for 8 weeks and were instructed not to change their physical activity or dietary habits during this period.
Participants used the Nordic Musculoskeletal Questionnaire to rate the pain or discomfort of 9 areas in the body from 0 to 10 during the preceding year and week. The 9 scores were combined into a global pain score. Neuropathic symptoms were captured using the 6-item Neuropathy Total Symptom Score.
A significant reduction in pain intensity was observed for individuals in the HIIT group vs the control group (mean difference [MD], -5.4; 95% CI, -10.6 to -0.2; P =.041), whereas no significant difference between the MICT group and the control group was observed for global pain intensity. When including only participants who reached the required intensity in ≥80% of the exercise sessions, a significant reduction in pain intensity for individuals in the MICT group vs the control group was observed (MD, -9.2; 95% CI, -15.7 to -0.7; P =.033), as well as for participants in the HIIT group vs the control group (MD, -6.9; 95% CI, -12.5 to -1.2; P =.018). There was no statistical difference in the reduction of pain between the 2 exercise groups and no significant reduction of neuropathy symptoms in any group. The number of adverse events during the training intervention was similar between individuals in the MICT group and the HIIT group, but after adjusting for the number of training hours completed, the number of musculoskeletal adverse events was twice as high in the HIIT group.
Taken together, the results of this study showed that HIIT training can be a safe and effective method for reducing musculoskeletal pain in inactive individuals with T2D. The HIIT exercise training program had the additional advantage of taking less than half the time that the moderate program took with similar results, potentially making it more useful for individuals who are not able to exercise for extended periods of time.
Future studies with larger sample sizes, longer durations, and more precise pain assessments are warranted.
Cox ER, Gajanand T, Burton NW, Coombes JS, Coombes BK. Effect of different exercise training intensities on musculoskeletal and neuropathic pain in inactive individuals with type 2 diabetes – preliminary randomised controlled trial. Diabetes Res Clin Pract. 2020;164:108168.