If you have type 1 diabetes and enjoy going to mountains for trekking or hiking or you are on a weekend break to get away from the hectic pace of daily life, you must be mindful about the amount of exercise you indulge in. Though the pandemic may prevent you from doing so at present. Nonetheless, a new study from University of Western Australia reported in the Journal of Clinical Endocrinology & Metabolism has stated that exercise at a high altitude may increase the risk for hypoglycemia in patients with type 1 diabetes. Hence, they must carefully monitor their blood glucose levels at high altitudes.

The researchers undertook to examine the effect of acute hypoxia on blood glucose levels during two sessions of moderate-intensity exercise simulating high altitude (~4,200m; hypoxia)and sea level (normoxia) in seven persons with type 1 diabetes. Their blood glucose levels were measured before, during and after the exercise. “Participants cycled for 60 minutes on an ergometer at 45% of their sea-level V̇O2peak, and then recovered for 60 minutes”.

No fall in blood glucose levels was seen within the first 30 minutes of exercise in both conditions. However, a considerable decrease in blood glucose levels was noted under conditions of hypoxia compared to the normoxic conditions or pre-exercise levels after one hour of exercise and during recovery from the exercise. Although an increase in the carbohydrate oxidation rates (measured using respiratory gases) was seen in both exercise conditions, the rates were higher under the hypoxic condition versus the normoxic condition before, during, and after exercise. The oxidation rates declined to pre-exercise levels after the exercise.

Based on these findings, the study authors suggest that exercise at high altitudes may enhance risk of exercise-mediated hypoglycemia in persons with type 1 diabetes and that “future guidelines may have to consider the impact altitude has on exercise-mediated hypoglycemia”. This is important for their safety when they travel to high altitude areas to prevent hypoglycemia, which may even be potentially life-threatening if not managed in time.

Reference

1. Dugan CW, et al. Effects of simulated high altitude on blood glucose levels during exercise in individuals with type 1 diabetes. J Clin Endocrinol Metab. 2021 Dec 22;dgab881. doi: 10.1210/clinem/dgab881.