High Altitude Diabetes


I often feel like living with diabetes is an extreme sport. It may not involve much physical exertion, but the mental effort required — counting carbs, measuring exercise against insulin, worrying about lows while you sleep — is just as tiring, if not more so, than preparing for a test of athletic endurance. I mean, hell — a race eventually ends. Diabetes ain’t over till you’re dead.

Partially for this reason, I am not really into things labeled “extreme” (or, god help us, “x-treme”). Not extreme skiing, not extreme surfing, and certainly not Extreme Pizza, a chain near my old house in California. No, I prefer safety to adrenaline — and while I’m always up for adventure, I like there to be a safety harness attached.

Unfortunately, I’m about to wade into the waters of what I’ve decided can be classified as “extreme diabetes” — spending time at high altitude. My husband and I are currently traveling for several months before settling back down on the east coast, and our next adventure is traveling overland to Tibet. (Tomorrow, we take the train from Xining to Lhasa, on the world’s highest railway.) I’m forgetting the precise numbers right now, but Lhasa is pretty damn high. And it’s not the highest place we’ll be — at the end of our overland journey, just before the Nepal border, we’ll be at over 4,900 meters above sea level. That’s right: meters. That’s  more than 16,000 feet.  It’s up there.

So what does this have to do with diabetes? Several things. First, the symptoms of Acute Mountain Sickness — which include dizziness and confusion — are close to those of hypoglycemia. (If only our bodies had evolved more precise warning systems. There could be little codes — an itchy left ear means altitude sickness. Tingling in your right buttock means low blood sugar. Wouldn’t that be easier?) Second, if you’re dehydrated — as can easily happen when you’re on Diamox (a drug I’m taking to prevent altitude sickness) and traveling in dry places — the concentration of glucose in your blood can rise. Third, putting your body through the stress of adjusting to a lower oxygen atmosphere releases, you guessed it, stress hormones — which can increase insulin resistance. What’s more, high altitudes often are cold, which makes equipment work less well.

But the thing I’m most worried about isn’t my own body; it’s my glucometer. They’re not reliable at high altitudes. Abbott’s meters, for example, have been tested up to 10,000 feet above sea level — more than enough for your average vacation. But remember, this is Extreme Diabetes! At altitudes that high, glucometers just can’t keep up.

Already worried, I decided to try to find out which direction the inaccuracies tend to fall. Do the meters underestimate blood glucose levels, or overestimate them? Should I worry about false highs, or false lows? I did a little internet research — slightly more challenging than normal since I’m in China and some useful sites are blocked — and found this article, titled “Adventure Travel and Type 1 Diabetes.” It has a lot of great information, but this particular passage stuck out:

A significant number of studies have examined the accuracy and reliability of various glucose meters at altitudes ranging up to 5,800 m (46,10,4752), with all but a single report (6) indicating problems with glucose meter reliability at altitude.

Great. Even less reassuring?

In the author’s own experience (Fig. 1), six different glucose meters have been tested at altitudes of 0–4,800 m, with two glucose meters giving falsely high and four giving falsely low readings using control glucose solutions, by as much as 37%.

She concludes: “Overall, therefore, meter reliability at altitude must be considered suspect unless proven otherwise.”

The problem, of course, is how to prove anything otherwise when you don’t have a reliable control. She does recommend testing blood v. control solution on several different meters, which might be what I have to do — but that’s a far from perfect solution when you don’t have control over your diet, and you’re trying to figure out whether to take a correction bolus before you go to bed.

It’s moments like these that really make the uncertainties of diabetes hit home. It’s hard enough to figure out how to take a perfect bolus for a banana. Throw in 15,000 feet and a meter that can’t be trusted — and what the hell are you supposed to do? I remember a time when I hiked up a mountain (strangely enough, also in China) and the air was so humid that my glucometer stopped working. I didn’t have a backup with me, and the only food available was large bowls of noodle soup. I remember lying awake in bed that night feeling paralyzed with uncertainty — I didn’t know whether I was high or low. And the difficulty snowballed — if you don’t know where your blood sugar is before breakfast, how are you supposed to bolus for the meal? Luckily, I returned to Beijing (and my backup supplies) the following day, having learned the lesson of always bringing backups, just in case something goes awry.

Which leads me to the finale of the Adventure Sports article, an anecdote that I enjoyed both for the author’s academic tone, and the foolishness of the man she encounters:

In her own high- and extreme-altitude travels over the course of nearly a decade, the author has only encountered one other individual with type 1 diabetes. Regrettably, this person failed to plan appropriately for travel with diabetes, resulting in an unhappy outcome. In this particular case, the individual did not feel it necessary to inform the travel company that he had type 1 diabetes, and he did not take a single glucose meter with him on his 20-day trip to extreme altitude. After developing severe gastroenteritis, the travel company felt that he was not sufficiently competent to care for himself, and they took the decision to medically evacuate him (by donkey!); he and his wife ruined their trip, although, fortunately in this instance, nothing worse happened.

I’m not sure what’s going to happen with my own high-altitude adventures, but I can promise you this: no donkey evacs will be involved.

Notify of
oldest most voted
Inline Feedbacks
View all comments
Dana Callen
Dana Callen
10 years ago

I am Type II traveling in Ecuador and in Quito (2850m, 9350ft). I had to have dinner late the other night (unplanned). When I tested post postprandial, my level was 317. Normally I would have to take 73 units of Humolog to bring that down to normal, near 100. I decided to be cautious and only take 50 units as a step-down strategy. I intended to retest after a few hours. Instead I woke up soaked in a wet bed of sweat, which I had to sleep in shivering because I didn’t have others available. I immediately grabbed my glucose… Read more »

11 years ago

Catherine– I also worried about altitudes when traveling to Tibet a few years ago, both for my meter and my pump, which I was warned could potentially leak insulin into my body when taken above a certain altitude–which combined with the possibility of my meter not working and the general feelings of unwellness and displacement that come with altitude…was an exciting prospect! I wound up taking a CGM with me, having been guaranteed by both my Diabetes Educator and the manufacturers that altitude shouldn’t affect its performance, and it was absolutely horrific. Sometimes as much as two hundred points off–and… Read more »

Copyright © 2009-2021 Diabetes Media Foundation, All Rights Reserved.
ASweetLife™ is a trademark of the Diabetes Media Foundation, All Rights Reserved.
Would love your thoughts, please comment.x