Managing changes in time zones
If you are crossing three or fewer time zones, insulin adjustment will most likely not be necessary. However, if you will be travelling across more than three time zones, there are a couple of general guidelines to follow. First, it is best if you are on a basal-bolus regimen or pump therapy, as opposed to premixed insulin, as this allows for more flexibility in your dosing. These types of changes to your treatment should be made a few weeks in advance of your trip, so that you can be sure your blood glucose levels are stable prior to departure. Always dose for meals and snacks with rapid-acting insulins (for example, NovoRapid® or Humalog®), as you would at home.
Managing insulin across changing time zones when heading EAST
If you are travelling east, this will shorten your day, and you will require less of your basal insulin. Once you have started your travels, give a reduced dose of your long-acting insulin at the usual time, which should be calculated by your healthcare team. After this dose, change your watch to the destination time and give your next dose of insulin at your usual time with your usual dose in the new time zone (for example, if you usually take insulin at 10:00 pm Toronto time, take your insulin at 10:00 pm according to your new time zone). This dose should be your usual number of units.
Managing insulin across changing time zones when heading WEST
If you are travelling west, this means your travel day will be longer. You will need more insulin and extra meals on the travel day. For example, if you are travelling west from Europe to Canada, you may gain about seven extra hours in time. When you arrive in Canada, you should have an extra meal, and you will then require an extra dose of rapid-acting insulin. This will last between four and six hours, and will assist with blood sugar control for the remainder of that day. You can then return to your usual routine, according to the time at your destination.
