Flying with Diabetes

Controlling Your Diabetes When Crossing Time Zones

An optimistic post that the world will open up again soon! 

We understand that it might seem a bit odd to post about traveling abroad given the current international COVID-19 crisis. Right now, those living with diabetes must be extremely cautious to avoid the coronavirus and we encourage all of you to please be careful out there.

That said, being grounded for the past few years has us fondly dreaming of the day when travel will be at least somewhat normalized again. In that spirit, we’re writing this post. We know there will come a time when you’ll want to spread those wings again and it will be safe to do so, therefore it’s with a great sense of optimism that we bring you this post with information and tips about crossing time zones with diabetes.

(Who knows, maybe you’re reading this article long after the pandemic has gone the way of the dinosaurs? We can always hope!)

Traveling across time zones with diabetes

Traveling with diabetes is easier today than it has ever been thanks to advancements in blood sugar testing and treatment options. Nevertheless, if you’ve been an avid traveler who has Type 1 or Type 2 diabetes, you know that there are a lot more considerations on your pre-flight checklist than what to squeeze into that over packed suitcase.

This is particularly true for those on a strict insulin regimen who travel overseas and cross multiple time zones. After all, the timing of insulin injections, whether  by syringe or insulin pen, is a major component of maintaining proper blood sugar control. But what happens when your normal routine is thrown out of whack while crossing time zones? 

What time zone is it anyway?

Okay, for the purposes of this article we’re going to assume that you are traveling to a time zone that is more than three hours different from where you live. If you’re only adding or losing an hour or two, it shouldn’t dramatically impact your insulin therapy plan. Simply take your normal dose as usual before you leave and once you arrive at your destination, switch your schedule to the local time and continue as normal. That’s it. However, if you travel across five or more time zones and end up in a place that’s four, five or even eight hours different than home, then you’re going to have to make some adjustments.

Traveling east

Anytime you travel east, your day will be shortened. According to the Sansum Diabetes Research Institute, a leading organization working towards the prevention and treatment of diabetes and founded by Dr. William Sansum, the first physician in the United States to administer insulin to a person with diabetes, here are some guidelines individuals who take a basal dose of insulin (long-acting) once or twice a day and are crossing five or more time zones should remember:

  1. The day before you depart, inject your normal dose of insulin at the usual time of day.
  1. Continue to follow the time zone you departed from once you take off.
  1. At your next scheduled dosage time, give yourself a reduced dose of your normal insulin. You’re probably wondering how much to reduce, right? It’s time for a little math. The following formula should be used to calculate the dosage reduction:

Travel Dose = Usual Dose x (0.9 - [number of time zones you’re crossing ÷ 24])

So, let’s work an example. If you’re crossing 5 times zones, the math goes like this:

– First, divide 5 by 24, which gives you .21

– Next, subtract .21 from 0.9 and you get .69

– Your Travel Dose = Your Usual Dose x .69

  1. After calculating and injecting your reduced dose, set your watch to the time in your travel destination.
  1. You’re now calibrated. Give your next dose of insulin at the hour you would normally take it but in the new time zone.
  1. It’s important to note that bolus (rapid-acting) insulin should be taken at mealtimes as directed by your doctor during your travels, regardless of time zone.

Traveling west

When you travel west, your day gets longer. Once again, according to the experts at the Sansum Diabetes Research Institute there are some adjustments to make to your insulin treatment plan. If you’re traveling west and take one or two basal injections a day, here’s what you need to remember:

  1. The day before you depart, inject your normal dose of insulin at the usual time of day.
  1. Once you begin traveling, keep your watch set to your departure time zone and give yourself half the normal dose of insulin at your normally scheduled time.
  1. After giving yourself this half dose, switch your watch to the destination time zone (if you don’t know it, check the world clock on your smartphone or ask your flight attendant).
  1. Next, administer the remaining half dose of basal insulin at the same hour you are accustomed to - but make sure you do it according to your new time zone. In other words, if you usually administer insulin at home in San Francisco at 7 pm, go ahead and take this half dose at 7pm in your new time zone.
  1. You’re now calibrated. Administer your next dose of insulin at the hour you would normally take it in the new time zone.
  1. It’s important to note that bolus (rapid-acting) insulin should be taken at mealtimes as directed by your doctor during your travels, regardless of time zone.

Users of twice-daily premixed insulin

If you use twice-daily premixed insulin, ask your diabetes physician to give you an insulin pen to travel with that has rapid-acting insulin lasting 4-6 hours. Then follow these guidelines:

  1. Take your pre-mixed insulin prior to departure at the normal time.
  1. While traveling, test your blood sugar every 4-6 hours. If it rises too high, administer a small amount of the rapid-acting insulin, preferably with a meal, to compensate. FYI, testing while traveling (and in general) can be made easier and more convenient with a continuous glucose monitoring (CGM) system, such as the FreeStyle Libre or Dexcom G6.
  1. Take your next dose of pre-mixed insulin at the scheduled time but in the new time zone.

It is important to note that all of these insulin guidelines, while carefully calculated, are not a replacement for instructions from your diabetes physician. Always make sure you speak with your doctor and care team well in advance of embarking on a trip abroad. Sometimes it is better to move to a different insulin regimen before traveling. Your doctor will know.


What about an insulin pump?

There’s no doubt that traveling with an insulin pump takes a lot of the math and guesswork out of crossing time zones. Most people just leave their pump settings the same and change the clock on their insulin pump to the new time zone after landing. Even if you’re crossing multiple time zones, just wait until you reach your final destination and make the change. Of course, be sure to carry enough infusion sets for your travels and test your blood sugar more often, either with test strips and a glucose meter or a CGM, as levels may fluctuate during long periods of travel.

Jet lag

One time change variable that’s a real issue for those with diabetes is the weariness of jet lag. Fatigue can be a problem for anyone traveling across time zones, but for those with diabetes, it can be dangerous. Being exhausted can lead to poor judgment at mealtimes; losing track of time, which can result in missed insulin treatments; forgetting to test your blood sugar on schedule; and other mishaps.

If possible, try to book flights that minimize the disruption in your sleep patterns. It’s also a good idea to try to get yourself used to the sleeping hours of the new time zone you’re visiting while traveling. For instance, if you’re in transit and it’s the wee hours of the night in the county you’ll be visiting, try to fall asleep on the plane. The sooner you get used to those new hours, the sooner you’ll get over that jet lag.

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