Increased Insulin Requirements During Exercise at Very High Altitude in Type 1 Diabetes Mellitus

  1. Henk J.G. Bilo, MD, PHD6,7
  1. 1Department of Internal Medicine, Canisius Wilhelmina Hospital, Nijmegen, the Netherlands
  2. 2Department of Internal Medicine, Radboud University Nijmegen Medical Centre, Nijmegen, the Netherlands
  3. 3Department of Cardiology, Tjongerschans Hospital, Heerenveen, the Netherlands
  4. 4Department of Nephrology, Leiden University Medical Centre, Leiden, the Netherlands
  5. 5Department of Endocrinology, Leiden University Medical Centre, Leiden, the Netherlands
  6. 6Department of Internal Medicine, University Medical Centre, Groningen, the Netherlands
  7. 7Department of Internal Medicine, Isala Clinics, Zwolle, the Netherlands
  1. Corresponding author: Pieter de Mol, p.demol{at}aig.umcn.nl.

Abstract

OBJECTIVE Safe, very high altitude trekking in subjects with type 1 diabetes requires understanding of glucose regulation at high altitude. We investigated insulin requirements, energy expenditure, and glucose levels at very high altitude in relation to acute mountain sickness (AMS) symptoms in individuals with type 1 diabetes.

RESEARCH DESIGN AND METHODS Eight individuals with complication-free type 1 diabetes took part in a 14-day expedition to Mount Meru (4,562 m) and Mount Kilimanjaro (5,895 m) in Tanzania. Daily insulin doses, glucose levels, energy expenditure, and AMS symptoms were determined. Also, energy expenditure and AMS symptoms were compared with a healthy control group.

RESULTS We found a positive relation between AMS symptoms and insulin requirements (r = 0.78; P = 0.041) and AMS symptoms and glucose levels (r = 0.86; P = 0.014) for Mount Kilimanjaro. Compared with sea level, insulin doses tended to decrease by 14.2% (19.7) (median, interquartile range) (P = 0.41), whereas glucose levels remained stable up to 5,000 m altitude. However, at altitudes >5,000 m, insulin dose was unchanged (36.8 ± 17 vs. 37.6 ± 19.1 islet equivalents [IE] [mean ± SD] P = 0.75), but glucose levels (7.5 ± 0.6 vs. 9.5 ± 0.8 mmol/L [mean ± SD] P = 0.067) and AMS scores (1.3 ± 1.6 vs. 4.4 ± 4 points [mean ± SD] P = 0.091) tended to increase. Energy expenditure and AMS symptoms were comparable in both groups (P = 0.84).

CONCLUSIONS Our data indicate that in complication-free individuals with type 1 diabetes, insulin requirements tend to increase during altitudes above 5,000 m despite high energy expenditure. This change may be explained, at least partly, by AMS.

  • Received October 25, 2010.
  • Accepted December 21, 2010.

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This Article

  1. Diabetes Care
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