Circulatory response to hydrotherapy and dry heat in individuals with type 2 diabetes

In total, 33 subjects aged 23–74 years were examined to observe the effect of exposure to warm water hydrotherapy (40ºC), local heating (40ºC) and global (whole body) dry heat at 30ºC and 40ºC on their circulation. Data from patients with type 2 diabetes (n=16, mean age=58.3±11.5 years, mean weight=88.1±16.4 kg) were compared to data from control subjects (n=17, mean age=52±14.2 years, mean weight=80.4±12.3 kg). Vascular occlusion was used to assess endothelial damage. Subjects with type 2 diabetes had an impaired circulatory response to warm water immersion, dry heat and the application of local heat to increase skin temperature. Blood flow, in general, was diminished in diabetics by at least 50% when comparing resting blood flow in diabetics to that in control subjects. The response to heat under any condition studied here was also severely impaired in subjects with diabetes. These findings suggest that the application of warmth to increase circulation in patients with diabetes may not be as beneficial as once thought. In addition, the diminished sensation seen in diabetic patients with sensory neuropathies may make prolonged heating of their limbs potentially dangerous. For these reasons, therapists should use heat with caution in patients with diabetes.