Cocks Matthew, Shaw Christopher S, Shepherd Sam O, Fisher James P, Ranasinghe Aaron, Barker Thomas A, Wagenmakers Anton J M
Research Institute for Sport and Exercise Sciences, Liverpool John Moores University, Tom Reilly Building, Byrom Street, Liverpool, L3 3AF, UK.
School of Exercise and Nutrition Sciences, Deakin University, Geelong, Victoria, Australia.
J Physiol. 2016 Apr 15;594(8):2307-21. doi: 10.1113/jphysiol.2014.285254. Epub 2015 Feb 24.
Skeletal muscle capillary density and vasoreactivity are reduced in obesity, due to reduced nitric oxide bioavailability. Sprint interval training (SIT) has been proposed as a time efficient alternative to moderate-intensity continuous training (MICT), but its effect on the skeletal muscle microvasculature has not been studied in obese individuals. We observed that SIT and MICT led to equal increases in capillarisation and endothelial eNOS content, while reducing endothelial NOX2 content in microvessels of young obese men. We conclude that SIT is equally effective at improving skeletal muscle capillarisation and endothelial enzyme balance, while being a time efficient alternative to traditional MICT.
Sprint interval training (SIT) has been proposed as a time efficient alternative to moderate-intensity continuous training (MICT), leading to similar improvements in skeletal muscle capillary density and microvascular function in young healthy humans. In this study we made the first comparisons of the muscle microvascular response to SIT and MICT in an obese population. Sixteen young obese men (age 25 ± 1 years, BMI 34.8 ± 0.9 kg m(-2) ) were randomly assigned to 4 weeks of MICT (40-60 min cycling at ∼65% V̇O2 peak , 5 times per week) or constant load SIT (4-7 constant workload intervals of 200% Wmax 3 times per week). Muscle biopsies were taken before and after training from the m. vastus lateralis to measure muscle microvascular endothelial eNOS content, eNOS serine(1177) phosphorylation, NOX2 content and capillarisation using quantitative immunofluorescence microscopy. Maximal aerobic capacity (V̇O2 peak ), whole body insulin sensitivity and arterial stiffness were also assessed. SIT and MICT increased skeletal muscle microvascular eNOS content and eNOS ser(1177) phosphorylation in terminal arterioles and capillaries (P < 0.05), but the latter effect was eliminated when normalised to eNOS content (P = 0.217). SIT and MICT also reduced microvascular endothelial NOX2 content (P < 0.05) and both increased capillary density and capillary-fibre perimeter exchange index (P < 0.05). In parallel, SIT and MICT increased V̇O2 peak (P < 0.05) and whole body insulin sensitivity (P < 0.05), and reduced central artery stiffness (P < 0.05). As no significant differences were observed between SIT and MICT it is concluded that SIT is a time efficient alternative to MICT to improve aerobic capacity, insulin sensitivity and muscle capillarisation and endothelial eNOS/NAD(P)Hoxidase protein ratio in young obese men.
肥胖会导致骨骼肌毛细血管密度和血管反应性降低，这是由于一氧化氮生物利用度降低所致。冲刺间歇训练（SIT）被认为是一种省时的中等强度持续训练（MICT）替代方案，但尚未对肥胖个体的骨骼肌微血管系统进行研究。我们观察到，SIT和MICT使年轻肥胖男性的微血管毛细血管化和内皮型一氧化氮合酶（eNOS）含量等量增加，同时降低了微血管内皮NOX2含量。我们得出结论，SIT在改善骨骼肌毛细血管化和内皮酶平衡方面同样有效，同时是传统MICT省时的替代方案。
冲刺间歇训练（SIT）被认为是一种省时的中等强度持续训练（MICT）替代方案，能使年轻健康人的骨骼肌毛细血管密度和微血管功能得到类似改善。在本研究中，我们首次比较了肥胖人群对SIT和MICT的肌肉微血管反应。16名年轻肥胖男性（年龄25±1岁，体重指数34.8±0.9 kg·m⁻²）被随机分配至4周的MICT组（以约65%的最大摄氧量进行40 - 60分钟的骑行，每周5次）或恒定负荷SIT组（每周3次，每次进行4 - 7个200%最大功率的恒定负荷间歇）。在训练前后从股外侧肌取肌肉活检样本，使用定量免疫荧光显微镜测量肌肉微血管内皮eNOS含量、eNOS丝氨酸（1177）磷酸化、NOX2含量和毛细血管化。还评估了最大有氧能力（最大摄氧量）、全身胰岛素敏感性和动脉僵硬度。SIT和MICT增加了骨骼肌微血管eNOS含量以及终末小动脉和毛细血管中eNOS丝氨酸（1177）磷酸化（P < 0.05），但在以eNOS含量进行标准化后，后一种效应消失（P = 0.217）。SIT和MICT还降低了微血管内皮NOX2含量（P < 0.05），且两者均增加了毛细血管密度和毛细血管 - 纤维周长交换指数（P < 0.05）。同时，SIT和MICT增加了最大摄氧量（P < 0.05）和全身胰岛素敏感性（P < 0.05），并降低了中心动脉僵硬度（P < 0.05）。由于在SIT和MICT之间未观察到显著差异，得出结论：SIT是MICT省时的替代方案，可改善年轻肥胖男性的有氧能力、胰岛素敏感性、肌肉毛细血管化以及内皮eNOS/烟酰胺腺嘌呤二核苷酸磷酸（NAD(P)H）氧化酶蛋白比率。
