The American Diabetes Association states that all levels of physical activity can be performed by people with type 1 diabetes who do not have complications and are in good blood glucose control (1). Extreme altitude mountaineering, defined as climbing at altitudes in excess of 5,000 m, creates physiological demands, especially in type 1 diabetic subjects, who might experience impaired pulmonary function (2). We present the metabolic control and symptoms of mountain sickness during the 2002 Alpinisti in Alta Quota (ADIQ) Expedition to Cho Oyu, which is the sixth highest Himalayan peak. Six subjects with type 1 diabetes and 10 matched nondiabetic individuals participated in the expedition. The type 1 diabetic subjects were free of long-term diabetes complications and experienced climbers; they were in good metabolic control before the expedition. The glucose profiles at time 0800, 1000, 1200, 1400, 1800, 2000, and 2200 and the insulin requirement were assessed. The 3-hydroxybutyrate concentration on capillary blood was also determined at 0800 and 2000. Retinopathy and albumin excretion rate were assessed before and after the expedition. One of 6 type 1 diabetic subjects and 3 of 10 control subjects ascended to the top of Cho Oyu (NS between groups).
The Lake Louise Scoring System (3) showed no difference between type 1 diabetic and nondiabetic subjects in their susceptibility to symptoms of altitude sickness. None of the type 1 diabetic subjects developed fresh retinal hemorrhages. No differences were observed in urinary albumin excretion rate. There was a worsening of HbA1c during the expedition in both control and type 1 diabetic subjects (5.4 ± 0.1% vs. 7.9 ± 06%, P < 0.01). During the ascent to the Cho Oyu, there was a progressive increase in daily insulin requirement (from 38 ± 6 units/day at 0 m to 51 ± 6 at 4,200 m, P < 0,001). A significant rise in the capillary glucose concentration at 0800, 1000, 2000, and 2200 was also observed. On the day the type 1 diabetic subject reached the top of the Chou Oyu, he had an insulin requirement of 56 units/day (34 units/day at sea level) and a mean plasma glucose concentration of 198 mg/dl. No changes in the daily glucose coefficient of variation were observed. No significant changes in the 3-hydroxybutyrate capillary concentration were observed at 0800 or 2000. In conclusion, we found that uncomplicated type 1 diabetic subjects can cope with extreme altitude mountaineering; however, this activity leads to a worsening of metabolic control. Moreover, our results suggest that all diabetic patients who want to deal with this activity need to be extremely trained to handle glucose monitoring and to vary dietary and insulin needs accordingly.