Med Sci Sports Exerc 2021 Mar 12. Epub 2021 Mar 12.
Physiology Department, Faculty of Medicine, Airlangga University, Surabaya, Indonesia Cardiovascular Research Group, School of Human Sciences (Exercise and Sport Science), The University of Western Australia, Perth, Australia Integrative Physiology Laboratory, Department of Kinesiology and Nutrition, College of Health Sciences, The University of Illinois, Chicago, IL Australian Research Council Centre of Excellence for Nanoscale Biophotonics, Adelaide Medical School, Faculty of Health and Medical Sciences, The University of Adelaide, Adelaide, Australia Institute for Photonics and Advanced Sensing, The University of Adelaide, Adelaide, Australia School of Electrical, Electronic and Computer Engineering, The University of Western Australia, Perth, Australia.
Introduction: Exercise training has anti-atherogenic impacts on conduit and resistance artery function and structure in humans and induces angiogenic changes in skeletal muscle. However, training-induced adaptation in cutaneous microvessels is poorly understood, partly due to technological limitations. Optical coherence tomography (OCT) is a novel high resolution imaging technique capable of visualising cutaneous microvasculature at a resolution of ~30μm. We utilised OCT to visualise the impacts of training on cutaneous microvessels, alongside assessment of conduit artery flow mediated dilation (FMD).
Methods: We assessed brachial FMD and cutaneous microcirculatory responses at rest and in response to local heating and reactive hyperaemia; pre- and post-training in 8 healthy men compared to age-matched untrained controls (n=8). Participants in the training group underwent supervised cycling at 80% HRmax, 3x/week for 8 weeks.
Results: We found a significant interaction (P=0.04), whereby increase in FMD was observed after training (post 9.83±3.27 % vs pre 6.97±1.77 %, P=0.01), with this post training value higher compared to control group (6.9±2.87 %, P=0.027). FMD was not altered in the controls (P=0.894). There was a significant interaction for OCT-derived speed (P=0.038) whereby a significant decrease in the local disc heating response was observed after training (post 98.6±3.9 μm.sec-1 vs pre 102±5 μm.sec-1, P=0.012), whilst no changes was observed for OCT-derived speed in the control group (P=0.877). Other OCT responses (diameter, flow-rate and density) to local heating and reactive hyperaemia were unaffected by training.
Conclusions: Our findings suggest that vascular adaptation to exercise training is not uniform across all levels of the arterial tree; while exercise training improves larger artery function, this was not accompanied by unequivocal evidence for cutaneous microvascular adaptation in young healthy subjects.