Trek, altitude and diabetes

Know is the key to success. To go step by step, to learn from each experience. Our bodies, our diabetes are "machines" complex. The characteristics of the trek (duration, intensity, altitude, weather conditions), the available supply, our moral and physical condition all have an influence on our blood sugar control. From an article "Sports & Diabetes: a history of hormone", article I wrote for the journal "Nutrition Endocrinology" - No special EASD September 2014 Increasingly diabetes type1 (T1D) is engage in high-altitude treks, sometimes at a key summit. But the specific conditions at high altitude (> 3000 m) make the mountain a hostile environment for humans. Extreme temperatures aloft, the wind amplifies, are associated with a reduced atmospheric pressure, responsible for the partial pressure of O2 drops of the inspired air. The altitude is thus linked to a decrease in blood pressure in O2. The 'high mountain acclimatization thus refers to the reaction to physiological processes that prolonged exposure to hypoxia (= less oxygen) mandatory adjustments to the human body.

• Hypoxia is accompanied by hyperventilation with hypocapnia and respiratory alkalosis associated with an increased urinary elimination of bicarbonates. The buffering capacity of the blood decreased, promotes faster decompensation to ketoacidosis in a diabetic subject which would be unbalanced.
• Hypoxia also affects the concentration of certain hormones. The release of catecholamines (adrenaline and noradrenaline) is accompanied by hepatic glucose production when cortisol is responsible for insulin resistance. The altitude thus disturbs glucose control to hyperglycemia. In T1D, the lack of endogenous insulin does not allow the control loop / feedback control function properly.

Hyperglycemia and ketoacidosis risk is greater than that of hypoglycemia. Hence the importance of regular blood glucose checks to adjust insulin doses in altitude will usually increased, and this, even if the effort is intense and low energy intake (3).

Finally, the high altitude is sometimes synonymous with acute mountain sickness (AMS) resulting from the impairment of cerebral blood flow related to hypoxia and ventilatory changes. The symptoms are nonspecific (headache more or less intense, gastrointestinal disturbances, dizziness ...) but the most severe forms (pulmonary and cerebral edema) are alerted. T1D do not appear to be most affected: the acclimatization is largely genetically determined. But the hypoglycemia symptoms can sometimes be confused with those of AMS. Many questions arise, however, around the Diamox® (acetazolamide) used in prevention / treatment of AMS, emphasizing that the renal excretion of bicarbonate increases the risk of ketoacidosis.
[NB: to climb Kilimanjaro , the whole team has been advised to take Diamox®; 2 people on 12 DT1 did not wish to take. A stopped at 5400 m; the other was at the top with the rest of the team].

To date, no cons-indication is issued strictly for the stay in the mountains for type 1 diabetics free of any complications. However, exercise in such an environment can cause specific problems that must be known and understood by T1D to best prepare his stay and anticipate potential complications. Many glycemic control are needed throughout the trek and climb to adjust insulin doses.
The diabetic will also ensure the preservation of its insulin, which in high altitude may undergo many thermal variations (night vs. daytime temperatures and freezing temperatures from certain altitudes) making it progressively inactive. As its resucrage, its water and its glucose units, insulin will be kept closer to the body to minimize the thermal shocks and the gel. Moreover, the devices glycemic pretend sometimes under or overestimate the results, it is necessary to have two different well as visually readable strips. Those using glucose dehydrogenase would be more reliable than using glucose oxidase. To this is added the altitude polycythemia, beneficial for the transport of oxygen, but can underestimate the capillary blood glucose results.

The absence of endogenous insulin production increases the challenge for type1 diabetic athlete. However, adherence to daily and during physical activity is the key to that bright DT1 person fully his physical activities, sometimes extreme.

References (1) Yardley et al, 2013. Resistance versus aerobic exercise. Acute effects on glycemia in type 1 diabetes. Diabetes Care. 2013 March; 36 (3): 537-42. doi: 10.2337 / dc12-0963. Epub 2012 Nov. 19 (2) Galassetti et al, 2013 -. Exercise and type 1 diabetes (T1DM). Compr Physiol. 2013 Jul; 3 (3): 1309-1336. doi: 10.1002 / cphy.c110040. (3) De Mol et al, 2014 - Physical activity at altitude. Challenges for people with diabetes: a review. Diabetes Care. 2014 Aug; 37 (8): 2404-13. doi: 10.2337 / dc13-2302.