Metabolic and cardiovascular parameters in type 1 diabetes at extreme altitude.

Abstract

The American Diabetes Association states that physical activity can be performed by individuals with Type 1 diabetes. Nevertheless, extreme altitude mountaineering represents a demanding challenge. We present the metabolic and cardiovascular parameters found in individuals with Type 1 diabetes during the ascent to Cho Oyu located at a height of 8201 m. Six individuals with Type 1 diabetes and 10 matched controls participated in the expedition. Both groups were evaluated before and after 4 h of trekking for vital indices, blood gases, acute mountain sickness, and metabolic control at 0, 3700, and 5800 m. No difference between the groups was observed in acute mountain sickness scores. There was a progressive elevation in basal heart rates in both groups at increasing altitude while no changes were observed in mean blood pressures. After the 3 h of trekking, a significant increase in heart rate was observed in the controls at 0 m whereas a significant decrease in blood pressure was observed at higher altitude only in controls. HbA1c levels were worse after the expedition in both groups. A progressive increase in insulin requirement was observed in subjects with Type 1 diabetes (38 +/- 6 U x d(-1) at 0 m to 51 +/- 6 at 4200 m, P < 0.001). At an altitude of 5800 m, there was a significant increase in blood lactate concentration, independently of the activity level in the two groups. At extreme altitude, highly motivated trekkers with Type 1 diabetes but free from long-term complications present metabolic and cardiovascular parameters comparable with those of control subjects despite a worsening in metabolic control. This type of physical activity must be accompanied by careful glucose monitoring.