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From Palm Harbor, Florida, USA:

My 15-year-old son is training for a 3 mile run to meet a requirement for his Adult Black Belt in a few weeks. He will be running in hot, humid Florida weather. He experiences lows during hard exercise. We have tried reducing the basal up to 50% (pumping) 1 1/2 hours before he runs, carbohydrate loading 60 to 90 (which makes him feel too full and uncomfortable), and he still runs low. We tried disconnecting but then we got ketones/rebound. His endocrinologist suggested trying mini-glucagon since this will not be a recurrent activity (my son doesn't like to run). He suggested 10 units before the run and every 2 hours as needed during this 6 to 7 hour testing day. Only the run is in 90 degree weather and the rest of the day is in air conditioning, so I expect that we will not need it beyond the run. Excitement may increase his blood sugar when in the karate testing portion. My son doesn't do well in the heat, which is why we do indoor karate. Could his sensitivity to heat be causing this problem and is mini-glucagon the best solution? The 3 mile run is mandatory to continue the rest of the day. The karate school is flexible if he needs recovery time but not for the timed run. He has been training for about 6 weeks with great difficulty. Do athletes use mini-glucagon on occasion?


It sounds like small but frequent bursts of fast acting carbohydrates (i.e., juice, fruit, candy) should work coupled with ongoing basal insulin but at reduced rate. If there is no adrenalin/"anxiety" surge for him, this should work. Also, using the Medtronic CGM or the DexCom sensor would also be very helpful since he could detect trends before bottoming out.


Since we posted this question, a study was conducted to determine if giving a minidose of glucagon prior to exercise would indeed help prevent exercise induced hypoglycemia. The results of the study, which included 15 adults, indicated that the mini dose is effective. See Minidose Glucagon for Exercise-Induced Hypoglycemia in T1D.

Additional comments from Gary Scheiner, MS, CDE:

Several strategies should help. I agree that using a CGM would be a tremendous asset during a day like this with a variety of activities taking place. Rising or falling blood sugars would obviously require different adjustments than blood sugars that are stable - regardless of the level.

Adjusting basal insulin is not likely to help prevent hypoglycemia during a 20 to 30 minute run. If the run takes place within 90 minutes of a meal, the bolus dose at the meal should be reduced. If the run is not after a meal, watch the glucose level heading into the run and use a carbohydrate containing beverage (such as a sports drink) to prevent a drop (if necessary). Someone your son's age/size will probably need around 30 grams of carbohydrate to keep his blood sugar level during a 5k run. He should consume the carbohydrates 15 to 30 minutes pre-run to give them a chance to digest before the run begins.

During the remainder of the day's events, assuming he will be active throughout the day, a temporary basal reduction (50% or more) can be helpful for preventing recurring lows and the need to consume large amounts of food.

Of course, all of these adjustments could be for naught. With these types of "event" days, blood sugars sometimes run very high due to stress hormone production. If you combine high blood sugar with dehydration (from the heat/humidity), it is possible to become ketotic or develop heat stroke. A lot of water will be necessary, as will sufficient insulin; don't disconnect from the pump for more than an hour at a time without bolusing to replace missed basal insulin. It is always a good idea to relax and enjoy the day rather than becoming uptight or highly competitive.


Original posting 20 May 2015
Posted to Exercise and Sports and Other Medications


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Last Updated: Wednesday September 20, 2017 12:27:11
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