Physical activity at altitude: challenges for people with diabetes: a review.

BACKGROUND A growing number of subjects with diabetes take part in physical activities at altitude such as skiing, climbing, and trekking. Exercise under conditions of hypobaric hypoxia poses some unique challenges on subjects with diabetes, and the presence of diabetes can complicate safe and successful participation in mountain activities. Among others, altitude can alter glucoregulation. Furthermore, cold temperatures and altitude can complicate accurate reading of glucose monitoring equipment and storage of insulin. These factors potentially lead to dangerous hyperglycemia or hypoglycemia. Over the last years, more information has become available on this subject. PURPOSE To provide an up-to-date overview of the pathophysiological changes during physical activity at altitude and the potential problems related to diabetes, including the use of (continuous) blood glucose monitors and insulin pumps. To propose practical recommendations for preparations and travel to altitude for subjects with diabetes. DATA SOURCES AND SYNTHESIS We researched PubMed, medical textbooks, and related Internet sites, and extracted human studies and data based on relevance for diabetes, exercise, and altitude. LIMITATIONS Given the paucity of controlled trials regarding diabetes and altitude, we composed a narrative review and filled in areas lacking diabetes-specific studies with data obtained from nondiabetic subjects. CONCLUSIONS Subjects with diabetes can take part in activities at high, and even extreme, altitude. However, careful assessment of diabetes-related complications, optimal preparation, and adequate knowledge of glycemic regulation at altitude and altitude-related complications is needed.