Key result
HIIT improves endothelial function vs. MCT, increasing FMD by ~6%.
Why the study?
To compare the effect of high-intensity interval training with moderate-intensity continuous training on endothelial function, oxidative stress, and clinical fitness in patients with type 1 diabetes.
Does high-intensity interval training improve endothelial function and cardiorespiratory fitness in patients with type 1 diabetes compared to moderate-intensity continuous training?
RCT (n=36)
Single-blind
Block randomization
No
Does high-intensity interval training improve endothelial function and cardiorespiratory fitness in patients with type 1 diabetes compared to moderate-intensity continuous training?
Absolute Event Rate: 5.5% vs 0.2%
p-value: p=0.0074
In patients with type 1 diabetes, 8 weeks of high-intensity interval training produced greater improvements in endothelial function and physical fitness compared to moderate-intensity continuous training.
High-intensity interval training may be preferred over moderate-intensity continuous training for endothelial function in type 1 diabetes; extends RCT evidence to this population.
To compare the effect of high-intensity interval training (HIIT) with moderate-intensity continuous training (MCT) on endothelial function, oxidative stress and clinical fitness in patients with type 1 diabetes. Thirty-six type 1 diabetic patients (mean age 23.5±6 years) were randomized into 3 groups: HIIT, MCT, and a non-exercising group (CON). Exercise was performed in a stationary cycle ergometers during 40 min, 3 times/week, for 8 weeks at 50-85% maximal heart rate (HRmax) in HIIT and 50% HRmax in MCT. Endothelial function was measured by flow-mediated dilation (endothelium-dependent vasodilation [EDVD]), and smooth-muscle function by nitroglycerin-mediated dilation (endothelium-independent vasodilation [EIVD]). Peak oxygen consumption (VO2peak) and oxidative stress markers were determined before and after training. Endothelial dysfunction was defined as an increase <8% in vascular diameter after cuff release. The trial is registered at ClinicalTrials.gov, identifier: NCT03451201. Twenty-seven patients completed the 8-week protocol, 9 in each group (3 random dropouts per group). Mean baseline EDVD was similar in all groups. After training, mean absolute EDVD response improved from baseline in HIIT: +5.5±5.4%, (P=0.0059), but remained unchanged in MCT: 0.2±4.1% (P=0.8593) and in CON: -2.6±6.4% (P=0.2635). EDVD increase was greater in HIIT vs. MCT (P=0.0074) and CON (P=0.0042) (ANOVA with Bonferroni). Baseline VO2peak was similar in all groups (P=0.96). VO2peak increased 17.6% from baseline after HIIT (P=0.0001), but only 3% after MCT (P=0.055); no change was detected in CON (P=0.63). EIVD was unchanged in all groups (P=0.18). Glycemic control was similar in all groups. In patients with type 1 diabetes without microvascular complications, 8-week HIIT produced greater improvement in endothelial function and physical fitness than MCT at a similar glycemic control.
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Boff et al. (2019) conducted an RCT in Type 1 Diabetes (n=36). High-intensity interval training (HIIT) vs. Moderate-intensity continuous training (MCT) and non-exercising control (CON) was evaluated on Difference between post- and pre-training percentage flow-mediated dilation (FMD) (p=0.0074). High-intensity interval training for 8 weeks significantly improved endothelial function, increasing flow-mediated dilation by 5.5% from baseline, compared to moderate-intensity continuous training.
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