Ain’t No Mountain High Enough: Managing Diabetes in High Altitudes (Part II)

Zachary McCune_Squaw Valley
Zack McCune snowboarding in Squaw Valley, California

While there are many people who enjoy snowboarding, skiing, and hiking in the mountains, there are others who like push the limits even further. Some consider climbing into the clouds to reach mountaintop summits to be the ultimate test of mind and body. For people managing diabetes, mountain climbing can present even more challenges. In the second installment of our two part series, we take a look at what you need to know when your winter activities involve extreme altitudes.

In the U.S., some of the highest ski resort summits are Beaver Creek at 11,440 ft, Vail at 11,570 ft, and Breckenridge at 12,998 ft. But what if you’re planning on going even higher? Mount Whitney in California has a 14,505 foot summit, Kilimanjaro is 19,308 feet above Tanzania, and Ojos del Salado is a whopping 22,608ft in the air. There’s a lot more to think about than the cold. “At those altitudes it’s pretty complex in that there are a lot of physiological changes that impact the diabetes,” says Jacqueline Shahar, M.Ed., RCEP, CDE, a Certified Diabetes Educator and Manager of Exercise Physiology at Joslin Diabetes Center.

Although it hasn’t been studied extensively, there have been a few studies monitoring climbers with type 1 diabetes as they ascended steep peaks. Besides being attentive to problems experienced at lower mountain altitudes like decreased temperatures, exacerbated diabetic neuropathy from the cold, and increased risk of low blood sugar from low oxygen and increased physical activity, you also have to be aware of worsening diabetic retinopathy. The increased altitude can worsen the affect diabetes has on your eyes and even cause retinal hemorrhages, so make sure to have a thorough eye exam and an okay from your doctor before embarking on a high altitude climb.

There is also an unusual risk for developing ketoacidosis during your climb. Ketoacidosis is a serious complication that occurs when the body cannot use sugar (glucose) as a fuel source because there is no insulin or not enough insulin. Fat is used for fuel instead, causing an increase of acids (ketones) in the blood. If left untreated ketoacidosis can lead to diabetic comas and even fatalities. Patients who developed Acute Mountain Sickness (AMS) are far more likely to develop ketoacidosis. AMS is caused by reduced air pressure and lower oxygen levels at high altitudes (anything over 8,000ft can cause AMS). The faster you climb to a high altitude, the more likely you will get acute mountain sickness. Symptoms may include:

  • Difficulty sleeping
  • Dizziness or light-headedness
  • Fatigue
  • Headache
  • Loss of appetite
  • Nausea or vomiting
  • Rapid pulse (heart rate)
  • Shortness of breath with exertion

Symptoms that may occur with more severe acute mountain sickness are:

  • Blue color to the skin (cyanosis)
  • Chest tightness or congestion
  • Confusion
  • Cough
  • Coughing up blood
  • Decreased consciousness or withdrawal from social interaction
  • Gray or pale complexion
  • Cannot walk in a straight line, or walk at all
  • Shortness of breath at rest

People with diabetes aren’t any more likely than those without diabetes to develop AMS, but the affects can be much more harmful. The problem, Jackie explains, is when people have a loss of appetite, nausea, or vomiting they are not eating—so they assume they should drastically lower their insulin doses. However, their bodies are also becoming dehydrated. Too little insulin and too little water can cause a dangerous swell in ketones which can lead to full blown diabetic ketoacidosis.

“I recommend bringing a glucogen kit as part of your diabetes supplies,” says Jackie. “It may feel like a low blood sugar if they’re at a high altitude. Blood pressure can drop, so that would be confusing,” says Jackie, explaining warning signs of AMS onset ketoacidosis. “It’s important to listen to your body, stay hydrated, and check your blood sugar.”

Even though these symptoms may sound scary, Jackie doesn’t dissuade people from mountain climbing. As long as they visit their doctor to make sure they’re healthy, educate themselves on the risks and warning signs, and thoroughly prepare for the trip, they should be able to scale peaks just like anyone else.

If you are planning a mountain climbing expedition, make sure to get a health screening with your endocrinologist and eye doctor. You should also talk to an exercise physiologist like Jackie to get tips and training for completing a safe climbing expedition.

If you want to learn more about diabetes management challenges unique to wintertime mountain activities, be sure to read our first post. For more information about balancing diabetes with wintertime activities or to make an appointment with one of Joslin’s exercise physiologists, click here.


  1. Two years ago I moved to 9,500 altitude. I’ve been a type 1 diabetic for 28 yrs and just recently developed diabetic retinopathy. My rental specialist is 3 hrs away and is the only option I have. I feel like I’m on an assembly line when I go in for laser treatments so I don’t have a lot of confidence in anything he says.
    My question is – I’m acclimated to the elevation but could the lower pressure be making my retinopathy worse?

  2. Courious –
    I an a “very” amateur mountain climber. Highest peak is 12,000, but we don’t get much higher than that in the Pacific North West. I wear an insulin pump which is a wonderful device that has made it easier for me on so many different adventures. I have searched websites everywhere, and the best information I can find notes that no insulin pump is warrantied over 10,000 feet. That goes for Animas, Medtronic, Tandem and even the old Disatronic.

    Anybody out there have any information of history about what altitude does to a pump. I know the waterproof ones have the potential for some pressure differential problems. Also curious to know what any other type 1s who climb do. I am guessing most on most mountains in the lower 48 wouldn’t worry about it, and would just climb with their pump.

    • I have had a major issue with my medronic pump not working at over 10-11,000 feet. I was forced to stop at 14,100 last summer on Elbert(14,300) because every step got to where it was like walking thru molasses. Upon return Doc said ,yeah this happens to pumps all the time. It sucked

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