Managing insulin with increased activity during travel

Some time ago one of our readers asked a question about managing insulin with increased activity during travel:

"My son is going to Europe for 6 weeks. He is currently a university student and does not have time for a lot of exercise. On his trip he will be active, walking and biking. Does anyone have an idea how much to cut down on his Lantus? He will clearly need to check his blood more to assess the efficacy of the new Lantus dose, but where should he begin; 1/2?"

Each person’s diabetes is very individual and that is the purpose of patient-centered services such as diabetes education, self-management training and information services offered by Diabetes Education Centers.

Dr. Bruce Perkins of the Leadership Sinai Centre for Diabetes, Mount Sinai Hospital, Toronto offers the following general principles around the use of basal insulin(e.g. Lantus®) which I hope others in similar situations will find helpful:

“First, the basal insulin's job is to provide that background insulin meant to keep the blood sugar stable between meals and prevent overproduction of ketones - too much and sugars drop while fasted or more active, too low and we struggle with rising blood sugars between meals and overnight. So the first question is whether the basal insulin dose is in a reasonable range even before going to travel. For example, does the blood sugar rise from bedtime to morning even without food/bolus insulin after dinner indicating too little basal? Does blood sugar drop if one skips or delays lunch indicating too much? If basal seems too high, then it should definitely be decreased whether going traveling or not, but if it seems too low or just right, it might be best not to adjust the Lantus at the start of the trip.

For exercise, we can think of three strategies:

1. Eat extra carbs during each exercise session (if one doesn't have experience with this, about half a gram per kilogram of his weight for the first hour of "ExCarbs" - extra carbs for exercise - is a good starting point). For example, a 60kg person could take 30 grams of extra carbs (2/3 of a gatorade bottle, for example) through the first hour of activity, then check BG the next hour to see if another 30g is needed. Be ready have available 30g of ExCarb per hour - carry gels, for example.
2. Reduce the bolus before exercise - It is breakfast on the morning of a hike through a European city. If that person needed the 30g of ExCarbs for the first hour, they could take less insulin for breakfast - if he carb counts and is eating 80 grams of carbs, he would only bolus for 50g. This leaves the 30g ExCarbs free of the effect of bolus insulin for the muscles to take up during the activity.
3. Reduce basal insulin - this works best for pump users, because when you reduce basal with Lantus, it not only reduces the basal during the exercise, but for the whole day. For pump users we suggest starting with a 50% temporary basal 1.5 hours before the start of the activity until the end.

I hope that this discussion helps, but ultimately this traveller on Lantus® has two options:

1. Keep the Lantus® the same, especially if pre-travel basal seems good or too low. He can follow steps 1 and 2.
2. If now basal might be too high, or if really uncertain, there's little harm in making a small (20%) reduction on the first few days and follow the BG trends to decide whether to continue with this.”

Dr. Perkins had some general advice regarding travel to Europe which others in similar situations would find helpful:

To take the Lantus® the evening of the flight to Europe on the plane, and then get the next bedtime dose at bedtime in Europe.

1. Check BG more often than on a typical day.
2. Have 'ExCarbs' and hypo treatment on you at all times.
3. Be organized with your supplies - talk to your team if you haven't before.
4. Enjoy the trip, be safe, and learn more about your own diabetes from the expedition.

There are excellent resources at most universities when it comes to ongoing peer support and lifelong learning with diabetes. Diabetes Canada has a chapter at University of Toronto (CADUT). Also, other campuses host a variety of informative events including Student Buddy Fair, and community presentations revealing some of the cutting-edge diabetes research occurring at the University of Toronto.