Patterns of circulating cytokines after 2 types of exercise in active type-1 diabetic patients

Aerobic training (beneficial for type 1 diabetes mellitus (T1DM) patients) could result boring, leading to inactivity or suboptimal performance. Therefore, High-Intensity Interval Training (HIIT) could be an appealing alternative. The present study aimed to compare modulation of certain inflammatory cytokines in T1DM participants performing aerobic vs. HIIT routines. We recruited 26 T1DM male subjects: ages 18-40, T1DM ≥ 2 years, glycated hemoglobin < 8.5%, stable insulin regimen for 6 months, minimum 90 min weekly physical activity and completion of International Physical Activity Questionnaire (IPAQ). IPAQ:2 corresponds to moderate activity and IPAQ:3 to intense physical activity. Participants performed a single aerobic or HIIT session separated by at least 72 h. Blood plasma samples were collected 20 min before and after each session. Cytokines were measured using LUMINEX technique. After aerobic exercise, pro-inflammatory cytokines interleukin (IL)-1β, IL-6, IL-7, IL-8, IL-17 A, tumor necrosis factor-α (TNF-α) and interferon-γ (IFN-γ) showed no significant differences in participants (IPAQ:2 and 3). Only anti-inflammatory cytokine IL-2 increased significantly in IPAQ:3 participants. Compared to pre-exercise, post-exercise HIIT situation presented a similar pattern. The 4 participants (IPAQ:3) that voluntarily followed a 12-week HIIT routine, showed significant increases in IL-7, IL-8, and TNF- α, and the detection of the anti-inflammatory cytokine IL-22. Altogether, these results suggest that HIIT favors the presence of some pro-inflammatory cytokines. The anti-inflammatory action of certain cytokines, such as IL-22, should be considered for a possible compensatory action. Nevertheless, programs of interval exercises at moderate intensity could be at the moment a safe option for T1DM patients.