Increasing numbers of people with diabetes are seeking advice about participation in high altitude climbing, which has the problems of serious metabolic demands, a high likelihood of acute mountain sickness (AMS),¹ and leaving the climber remote from medical care. The American Diabetes Association states that “all levels of exercise, including leisure activities, recreational sports, and competitive professional performance, can be performed by people with type 1 diabetes who do not have complications and are in good blood glucose control”.² But, are all forms of sport suitable for people with type 1 diabetes? Lack of data on the effects of altitude on blood glucose control has led to reticence among members of the medical profession to endorse high altitude mountaineering for people with diabetes

The Diabetes Federation of Ireland Expedition to Kilimanjaro (4559 m) gave some indication of the potential hazards of extreme altitude for diabetic climbers.³ Symptoms of AMS, as measured by the well validated Lake Louise scoring system,⁴ occurred with similar frequency in diabetic and non-diabetic climbers, indicating that diabetes per se …