Home‐hit improves muscle capillarisation and eNOS/NAD(P)Hoxidase protein ratio in obese individuals with elevated cardiovascular disease risk

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 laboratory‐ 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 cardiovascular disease 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‐HIT) 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; body mass index 34.3 ± 5 kg m−2; V̇O2 peak 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 before and after training to assess changes in vascular enzymes, capillarisation, mitochondrial density, intramuscular triglyceride content and GLUT4 protein expression using quantitative immunofluorescence microscopy. Training increased V̇O2 peak (P < 0.001), whole‐body insulin sensitivity (P = 0.033) and flow‐mediated dilatation (P < 0.001), while aortic pulse wave velocity decreased (P < 0.001) in all three groups. Immunofluorescence microscopy revealed comparable increases in total eNOS content in terminal arterioles and capillaries (P < 0.001) in the three conditions. There was no change in eNOS ser1177 phosphorylation (arterioles P = 0.802; capillaries P = 0.311), but eNOS ser1177/eNOS content ratio decreased significantly 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 mic...

Clapping jumping jacks to improve endothelial function in obese adults: if you're happy and you NO it, clap your hands

“…In an article recently published in The Journal of Physiology , Scott and colleagues evaluated the effect of a virtually supervised at‐home HIT programme on muscle capillarization and muscle microvascular eNOS/NAD(P)Hoxidase ratio in obese individuals with elevated CVD risk (Scott et al . ).…”

“…Augmented capillarization measures may allow for an increased O 2 delivery and extraction, probably contributing to the higher seen with HIT training reported by Scott et al . () and throughout the literature in obese adults.…”

“…Scott et al . () eloquently demonstrated that a home‐based HIT programme can effectively improve vascular function, endothelial eNOS regulation, capillarization and myocyte adaptations in obese individuals. Another noteworthy finding, less touched on by the authors, is the improvement of cardiovascular risk markers after home‐based HIT intervention.…”

Advances for high‐intensity interval training prescription in obesity

“…In a recent issue of The Journal of Physiology , Scott et al . () brought new information to this scenario after evaluating the effects of a virtually supervised home‐based HIT protocol on metabolic and functional adaptations in the SM microvasculature of sedentary obese individuals with an elevated risk of cardiovascular disease (CVD). Thirty‐two participants (36 ± 10 years) were self‐allocated to home‐based HIT (Home‐HIT), home‐based MICT (Home‐MICT) or laboratory‐based HIT (Lab‐HIT).…”

“…() proposed active recovery (2 and 3 min, respectively) in their protocols, while Scott et al . () proposed passive recovery (1 min). The types of exercise were bodyweight exercise (Home‐HIT), cycling on a cycle ergometer (SIT) and walking/running on a treadmill (AIT).…”