Comparison of Two Different Sprint Interval Training Work-to-Rest Ratios on Acute Inflammatory Responses.

BACKGROUND The study aims to compare how work-to-rest ratio (W:R) influences insulin sensitivity (Si) and inflammatory responses following one session of sprint interval training (SIT). METHODS Thirteen men and two women completed a cross-over comparison of two SIT interventions-Tabata (TAB), 10 × 20-s sprints/10-s rest, and Wingate (WIN), 5 × 30-s sprints with 270-s rest. IL-6, IL-10, and TNF-α were assessed at baseline, immediately following, and 1 h after SIT, as well as prior to the 24-h post-exercise oral glucose tolerance tests (OGTTs). RESULTS Participants were 23.8 (±3.5) years old and 180.0 (±10.2) cm tall, weighed 78.5 (13.0) kg, and had 16.9 (±6.5) % body fat, with a mean VO2Peak of 42.0 (±7.9) ml kg(-1) min(-1). There were no differences in total work (kJ) between TAB (64.7 ± 12.0) and WIN (68.0 ± 15.0). Mean (±95 % CI) Si 24 h changed -2.8 (-5.1, -0.5) from baseline after TAB and -3.9 (-6.9, -0.9) after WIN. Cytokines were measured in pg ml(-1) and expressed as mean change (±95 % CI). IL-6 increased significantly immediately following SIT for TAB 0.70 (0.23, 1.17), and WIN 1.11 (0.60, 1.62), and remained elevated 1 h post SIT for TAB 1.10 (0.37, 1.83), and WIN 0.95 (0.26, 1.65). IL-10 showed a significant positive change immediately following exercise for TAB 1.53 (0.77, 2.29) and WIN 1.59 (0.58, 2.59). TNF-α also increased immediately both TAB 3.26 (1.57, 4.96) and WIN 3.05 (0.56, 5.54) and was directly proportional to IL-10 (r = 0.64, p < 0.0001). CONCLUSIONS W:R did not alter either the inflammatory or metabolic response following SIT nor does SIT improve 24-h Si, despite increased levels of IL-10.