Edinburgh Napier University

  High intensity intermittent training (HIIT) has been shown to reduce the risk of chronic conditions including the development of type 2 diabetes mellitus (T2DM). Independently, a low vitamin D status has also been linked to the prevalence of T2DM. The aim of this study was to investigate if there was a synergistic metabolic effect of HIIT and vitamin D supplementation on glycaemic control. Twenty male and female participants (age, 34 ± 9 y; BMI, 31.4 ± 2.8 kg·m-2) completed 6 weeks HIIT, and were randomised to ingest 100 µg/day of vitamin D3 or placebo. Response to an oral glucose tolerance test (OGTT) was determined at baseline and 72 h post-intervention. Glucose tolerance was improved as a result of the HIIT intervention, shown through a reduction in glucose and insulin concentrations during the OGTT, accompanied with a decrease in glucose (829 ± 110 to 786 ± 139 mmol·h-1·L-1; P=0.043) and insulin (8101 ± 4755 to 7024 ± 4489 mU·h-1·L-1; P=0.049) area under the curve (AUC). Supplementation increased 25-hydroxyvitamin D3 concentration by 120 % to a sufficiency status (P