To Bathe or Not to Bathe

Type 2 diabetes mellitus (T2DM) is characterised by chronic high blood sugar concentration (hyperglycaemia) and insulin resistance leading to a reduction in insulin sensitivity. These hyperglycaemic excursions can seriously impact metabolic, micro and macrovascular health. The total cost of the direct and indirect care of individuals with diabetes (\~90% T2DM) in the UK (United Kingdom) is £23.7 billion, equating to \~20% of the annual national health service (NHS) budget, with this projected to become unsustainable. Low-cost interventions to improve glycaemic control in these individuals are therefore warranted. Current interventions include pharmaceuticals, exercise and calorie restrictive diets. Pharmaceutical interventions carry a high financial cost, while exercise and diet programmes have a low adherence rate in individuals with T2DM. Heat therapy offers one potential low cost therapy. Immersion in a hot tub for 30 mins.day-1 for 10 days has been shown to reduce fasting plasma \[glucose\] and HbA1c in individuals with T2DM, which may be explained by acute (e.g. muscle) and chronic (e.g. reduced inflammatory status and increased heat shock proteins (HSP)) adaptations, although experimental evidence for these hypothesis are sparse. Other potential benefits include improved glycaemic control, insulin sensitivity, elevated resting metabolic rate and improved micro- and macrovascular function. The aim of the present study is to determine whether acute hot water immersion can improve glucose tolerance in individuals with T2DM and whether it is more beneficial to undertake this before or after a OGTT (oral glucose tolerance test).