Scott, SN, Shepherd, SO, Hopkins, ND, Dawson, EA, Strauss, JA, Wright, DJ, Cooper, RG, Kumar, P, Wagenmakers, AJM and Cocks, MS (2019) Home-HIT improves muscle capillarisation and eNOS/NAD(P)Hoxidase protein ratio in obese individuals with elevated cardiovascular disease risk. Journal of Physiology. ISSN 1469-7793

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Abstract

KEY POINTS: Obesity and sedentary behaviour are associated with capillary rarefaction and impaired muscle microvascular vasoreactivity, due to reduced nitric oxide bioavailability. Low-volume high-intensity interval training (HIT) is a time-efficient alternative to traditional moderate-intensity continuous training (MICT), but its effect on the muscle microvasculature has not been studied. The applicability of current lab- and gym-based HIT protocols for obese individuals with low fitness and mobility has been disputed by public health experts, who cite the strenuous nature and complex protocols as major barriers. Therefore, we developed a virtually-supervised HIT protocol targeting this group that can be performed at home without equipment (Home-HIT). This study is the first to show that 12-weeks of virtually-supervised Home-HIT in obese individuals with elevated CVD risk leads to similar increases in capillarisation and eNOS/NAD(P)Hoxidase protein ratio within the muscle microvascular endothelium as virtually-supervised home-based MICT and laboratory-based HIT, while reducing many of the major barriers to exercise. ABSTRACT: This study investigated the effect of a novel virtually-supervised home-based high-intensity interval training (HIT) (Home-HT) intervention in obese individuals with elevated cardiovascular disease (CVD) risk on capillarisation and muscle microvascular eNOS/NAD(P)Hoxidase ratio. Thirty-two adults with elevated CVD risk (age 36 ± 10 years; BMI 34.3 ± 5 kg∙m-2 ; V̇O2peak 24.6 ± 5.7 ml∙kg∙min-1 ), completed one of three 12-week training programmes: Home-HIT (n = 9); laboratory-based supervised HIT (Lab-HIT; n = 10) or virtually-supervised home-based moderate-intensity continuous training (Home-MICT; n = 13). Muscle biopsies were taken pre- and post-training to assess changes in vascular enzymes, capillarisation, mitochondrial density, intramuscular triglyceride content and GLUT4 protein expression using quantitative immunofluorescence microscopy. Training increased V̇O2peak (P < 0.001), whole-body insulin sensitivity (P = 0.033) and flow-mediated dilation (P<0.001), while aortic pulse wave velocity decreased (P < 0.001) in all 3 groups. Immunofluorescence microscopy revealed comparable increases in total eNOS content in terminal arterioles and capillaries (P < 0.001) in the 3 conditions. There was no change in eNOS ser1177 phosphorylation (arterioles P = 0.802; capillaries P = 0.311), but eNOS ser1177 /eNOS content ratio significantly decreased following training in arterioles and capillaries (P < 0.001). Training decreased NOX2 content (arterioles P < 0.001; capillaries P < 0.001), but there was no change in p47phox content (arterioles P = 0.101; capillaries P = 0.345). All measures of capillarisation increased (P < 0.05). There were no between group differences. Despite having no direct supervision during exercise, virtually-supervised Home-HIT resulted in comparable structural and endothelial enzymatic changes in the skeletal muscle microvessels to the traditional training methods. We provide strong evidence that Home-HIT is an effective novel strategy to remove barriers to exercise and improve health in an obese population at risk of CVD. This article is protected by copyright. All rights reserved.

Item Type:	Article
Additional Information:	This is the peer reviewed version of the following article: Scott, S. N., Shepherd, S. O., Hopkins, N. , Dawson, E. A., Strauss, J. A., Wright, D. J., Cooper, R. G., Kumar, P. , Wagenmakers, A. J. and Cocks, M. (2019), Home‐HIT improves muscle capillarisation and eNOS/NAD(P)Hoxidase protein ratio in obese individuals with elevated cardiovascular disease risk. J Physiol. Accepted Author Manuscript. doi:10.1113/JP278062, which has been published in final form at [Link to final article using http://dx.doi.org/10.1113/JP278062. This article may be used for non-commercial purposes in accordance with Wiley Terms and Conditions for Use of Self-Archived Versions.
Uncontrolled Keywords:	06 Biological Sciences, 11 Medical and Health Sciences
Subjects:	R Medicine > RC Internal medicine > RC1200 Sports Medicine
Divisions:	Sport & Exercise Sciences
Publisher:	Wiley
Related URLs:	Author
Date Deposited:	01 Jul 2019 10:50
Last Modified:	04 Sep 2021 09:14
DOI or ID number:	10.1113/JP278062
URI:	https://researchonline.ljmu.ac.uk/id/eprint/10949

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