Cardiovascular response to orthostatic stress following cold challenge in diabetics

Cardiovascular responses to cold pressor test (CPT) followed by orthostatic stress were investigated in diabetics and in control subjects. The test was performed by immersing the left hand (up to wrist joint) in water at 8 degrees C for 2 minutes. The blood pressure (BP) and heart rate (HR) were recorded immediately after removal of hand from water in recumbent state and then in erect posture. The orthostatic stress (without cold exposure) caused postural hypotension in diabetics, while in control subjects BP (both systolic and diastolic) increased on attaining erect posture. CPT alone increased HR, systolic blood pressure (SBP) and diastolic blood pressure (DBP) in control as well as in diabetics. In control subjects when CPT was followed by orthostatic stress, a marked statistically significant further increase in HR but fall in SBP was observed, though the increase in DBP was not significant. On the other hand statistically significant increase in HR, and decrease in SBP, DBP were observed in diabetic subjects. These impairments in cardiovascular responses are confirmative of autonomic neuropathy in diabetic subjects.