Need help navigating life with diabetes? You can always Ask D'Mine! Welcome again to our weekly advice column, hosted by veteran type 1, diabetes author and educator Wil Dubois. This week, Wil has some advice on how altitude affects insulin and what kind of blood sugar checks might work best for someone snacking between meals — stuff you won't want to miss!

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Edward, type 1 from Colorado, asks: Does altitude affect insulin action? I was on an extreme hike near Leadville and I had an extreme hypo at 13,185 feet. I've done many similar hikes at lower altitudes with no trouble, and this time I was running a temp basal rate on my pump and everything. Thoughts?

Wil@Ask D'Mine answers: My first thought is that anyone who goes on one extreme hike, much less "many" of them, needs to have their head examined. That said, does altitude affect insulin action? Most research shows it sure as hell does. The higher you go (are?) the more sensitive to insulin you become, and the less you need. The best advice seems to be what you'd expect: reduce your insulin, test more often, and keep the glucose handy.

Of course, not only does your insulin work differently at high altitude, so too does your body. The thinner air makes your body's respiratory and circulatory systems work harder, and that increases insulin uptake, again setting you up for lows if you don't cut back on your insulin usage. I couldn't find any message boards for extreme hiking type 1s (I probably just didn't look hard enough or walk far enough), but check out this discussion at the "Snowheads" forum.

Oops. Wait a second. Just to prove that nobody knows nothing about anything, and that your diabetes may vary, I found one study that claims just the opposite of all the other research and anecdotal experiences posted online. Last year researchers in the Netherlands forced eight type 1s on a 14-day trek up Mounts Meru and Kilimanjaro in Tanzania, and found that they all needed more insulin above 5,000 feet despite high energy expenditure. Go figure.

(I hope they at least planted the Blue Circle flag at the top of Kilimanjaro.)

Oh, and it's also worth mentioning two other little factoids: your pump may not work right at high altitudes and most glucometers are only rated up to 10,000 feet. So not only can your delivery be off, the information you're using to make decisions might be off, too. Lovely.

Hmmm... For your safety, may I recommend the alternate sport of extreme bikini watching at sea level?

Kathy, pre-diabetic from Kansas, writes: I have been measuring my blood glucose and working on losing weight/increasing activity since March, and am down 15 pounds, with more to lose.  I have been testing my blood sugar 7 times a day. When I wake up in the morning (BTW, I find that 90 minutes later, after exercise but before breakfast, my sugar is usually up then... what gives?), when I haven't eaten anything, and then before and after all my meals....

But, one evening a week, my knitting group meets from 6 to 8 p.m.  I have dinner that evening around 5:20 p.m, but we break for "treats" at 7 p.m. (two in the group are diabetic, two are pre-diabetic, four are blood-sugar-OK). Treats are often fruit or low-carb, but also sometimes rich & decadent — then I just have a little bit.  My question is whether I should test at 7, or if I should wait til 9 p.m. and test then, and just pretend I was having a 100-minute long dinner? Thanks, and I very much enjoy your column.

Wil@Ask D'Mine answers: I don't knit, but I'm ready to join your group! Oh, and good job on the weight loss, that's fabulous. Now...

Wait a second. You're pre-D and you test seven times a day? Are you a United States senator? Because either you have the world's best health insurance, or there's a lot more money in knitting than I realized. Forget extreme hiking, you're practicing extreme fingersticking!

Frankly, for someone who's not on any meds, you're probably over-testing. That said, if you can get or afford the strips, and you're finding the feedback on how various foods and activities affect your blood sugar, then more power to you. But I just want to make sure that you haven't lost that 15 pounds because you've spent so much on test strips that you can no longer afford food! If the strip spending is cutting into your yarn budget, you can probably learn almost as much by using fewer strips creatively.

As to your question about what's up in the morning, ironically, your exercise is increasing your blood sugar. Not to worry. Here's what's happening: A good workout pumps up your system for a bit. As you work out, your body releases cortisol, raising your blood sugar for a short time. Then as all the muscle action kicks in, the increased activity will vacuum the excess sugar out of your blood, and will continue to do so for hours and hours. So even though you see a rise after your workout, your workout will continue to work for you long after it is over.

And as to your question about knitting group treats, test at 9 p.m. Here's why: you don't have the knitting group six days per week, so you already know how dinner treats your sugar with a great deal of precision; you really don't need any more information about that. A more interesting question is how the weekly snack treats you, and to answer that question you need to re-arrange your testing on knitting night. You should wait until 9 p.m., but that's not all. I also want you to move your before-dinner test on that night. Instead of testing before dinner, test right before the snack, then two hours after it. That will show you how much the snack itself raises your blood sugar.

Remember not to get tied into knots about the numbers (the pre-snack number will be higher than you normally see, as it's closer after dinner than you usually test). Focus instead on the difference between the numbers. That's what matters.


This is not a medical advice column. We are PWDs freely and openly sharing the wisdom of our collected experiences — our been-there-done-that knowledge from the trenches. But we are not MDs, RNs, NPs, PAs, CDEs, or partridges in pear trees. Bottom line: we are only a small part of your total prescription. You still need the professional advice, treatment, and care of a licensed medical professional.

Disclaimer: Content created by the Diabetes Mine team. For more details click here.


This content is created for Diabetes Mine, a consumer health blog focused on the diabetes community. The content is not medically reviewed and doesn't adhere to Healthline's editorial guidelines. For more information about Healthline's partnership with Diabetes Mine, please click here.