High Altitude Travel Tips for Type 1 Diabetes

As you may already know, travel can have a big impact on type 1 diabetes (T1D) management. This is usually from things like stress hormones, time changes, different food options and other shifts in routine that can cause blood sugar levels to behave differently.

However, there are other things to consider when taking trips or exploring the outdoors that you might not take into consideration, like changes in altitude. And when it comes to planning a trip to a higher altitude, the main takeaway is that no one is affected the same way. So it’s best to be prepared for multiple outcomes.

Altitude sickness and diabetes

By far the most common side effect of being at high altitudes is altitude sickness, which can lead to (or simulate) symptoms that can affect type 1 diabetes (T1D) management.

Common symptoms of altitude sickness include:

• shortness of breath
• rapid heartbeat
• nausea
• exhaustion

All of this is due to decreased oxygen levels, but these symptoms are also common when suffering from hypoglycemia (low blood sugar). So it’s important to test your blood sugar levels often so you can distinguish between the two.

Blood sugar levels

High altitudes can increase your body’s production of stress-related hormones, which can raise blood sugar levels. If you plan on hiking or traveling to notably higher altitudes, talk to your healthcare provider about adjusting your insulin doses to compensate for its impact on your blood sugar levels.

While there’s no direct evidence that altitude causes low blood sugar, altitude symptoms can feel similar to hypoglycemia. Increased exercise like hiking or walking a lot while in high altitudes can definitely lead to lows. So check your blood sugar often.

Insulin resistance

There have been studies that suggest that higher altitudes can cause insulin resistance due to carbohydrates not being processed as easily and from the increase in stress hormones. 

This can be another cause of high blood sugar, and it can lead to diabetic ketoacidosis (DKA) in extreme cases. Talk to your healthcare provider about adjusting insulin doses to compensate for high altitude exercising or traveling.

Diabetes device function

Continuous glucose monitors (CGMs) and insulin pumps have been known to not work as effectively in high altitudes. CGMs in particular do not function well in cold weather below 40 degrees Fahrenheit, so be prepared to check blood sugar levels manually and often. 

Some blood glucose meters also do not work properly above a certain altitude, so you may also want to check with your meter and/or CGM manufacturers for further guidance.

There have also been some instances where certain insulin pumps deliver slightly more insulin at high altitudes and on airplanes, so be sure to read your pump manual or check with your pump manufacturer to learn more about how to avoid increased insulin delivery. This can help you avoid low blood sugar levels that seem to come out of nowhere.

Some tubeless, automated insulin delivery system (AID) users have reported issues when traveling to higher altitudes. These include exceedingly and unexpectedly low blood sugars because insulin is pushed through the cannula from the air pressure changes, followed by stubborn high blood sugar levels even after returning to a lower altitude. 

This can be very dangerous, especially if you’re sensitive to insulin, which is why some people prefer to return to manual daily injections (MDI) when they are ascending to higher altitudes, whether it’s air travel or hiking in the mountains. 

Other things to consider

It is always a good idea to meet with your healthcare provider before traveling, but especially to high altitudes. They may be able to provide you with medication to prevent altitude sickness, as well as advice on insulin dosing adjustments.

And remember to take your time when you travel to high altitudes. Pack extra supplies, insulin, water, snacks and lots of extra low snacks just in case.

Altitude sickness is most commonly caused by ascending too quickly. Be sure to keep a steady pace so that your body can acclimate—and take many breaks. The higher you climb, the less oxygen there will be. Keep this in mind to avoid exhaustion.

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