Effects Of High-intensity Interval Training Vs. Detraining On Cardiometabolic Health In Overweight And Obesity

High-intensity interval training (HIIT) is considered a time efficient strategy for enhancing cardiometabolic health in individuals with obesity. However, whether these positive effects can be sustained after the termination of HIIT is not well understood. PURPOSE: To examine the 2-week detraining effects of short-term (2-week) HIIT on cardiometabolic risk reduction in young adults with overweight and obesity. METHODS: Six young adults with overweight and obesity (4 males, 2 females; age 24.5 ± 5.6 [SD] years; body mass index 28.4 ± 3.2 kg/m2) completed 2 weeks of running based HIIT (3x per week). HIIT intensity was achieved at 90% of participants’ maximal distance at baseline and participants underwent a 1:5 work-to-rest ratio HIIT protocol (a total of 20 minutes per session). Note that, currently, five individuals have completed the 2-week detraining screening (data collection ongoing). After a 10-12 hrs of overnight fasting, body composition, physical fitness, lipids, glucose, and subclinical markers of cardiovascular disease were measured at pre- and post-HIIT (2-week), and after the 2-week detraining period. Repeated measures ANOVA with paired post-hoc tests were used to examine changes in outcome measures among baseline, post-HIIT intervention, and the detraining period. Statistical significance was set at p < 0.05. RESULTS: Total cholesterol and fasting glucose were reduced after HIIT and the detraining period vs. baseline (176.5 ± 6.3, 171.5 ± 3.2 vs. 187.0 ± 4.8 mg/dL, respectively, p = 0.05) and (91.2 ± 2.5, 92.2 ± 2.0 vs. 94.2 ± 2.1 mg/dL, p < 0.05). Central diastolic blood pressure was reduced after HIIT vs. baseline (67.8 ± 2.3 vs. 70.7 ± 2.2 mmHg, p < 0.05) and heart rate-corrected augmentation index was improved after HIIT vs. baseline (0.3 ± 3.5 vs. 4.8 ± 2.8 %, p < 0.05), with these improvements being sustained after 2 weeks of training cessation. There were no significant changes in body composition, physical fitness, or other cardiometabolic parameters after HIIT and the detraining period. CONCLUSIONS: Our data suggest that short-term HIIT is effective in improving lipids, glucose, and wave reflections. More importantly, these health benefits persisted over the 2-week detraining period. Long-term detraining effects of HIIT on cardiometabolic health should be uncovered.