Our 11 year old daughter (with type�1 for two years) plays competitive soccer league, we’ve just switched from NPH and Regular to Humalog at meals time with Lantus at bed time, and we are having difficulty figuring out how to make adjustments for the heavy physical activity. Today for example, she played a 75 minute scrimmage starting at 11:00 am (i.e., it was hot!), and with blood sugar tests, a pint of water, 20 ounces of Gatorade, and 12 ounces of orange juice (which is a lot for a lean 75 pound kid), we managed to keep her blood sugar in the 150 mg/dl [8.3 mmol/L] range throughout the game.

We are aware that exercise helps her body use insulin more efficiently and in fact routinely reduced the Regular and NPH doses on game and practice days. Still, she always had some circulating insulin in her body to help it absorb the energy from the carbs. Can we assume the same thing is true with the new routine? Taking today’s game as an example, the Humalog was long gone from her system by the time the game began. Therefore, the only insulin in her system would be from the Lantus. Would this be sufficient or should we be administering a small dose of Humalog (perhaps 1 unit to start) at game time? If the game is late in the evening as 7:00 pm (in which case she would have had her Humalog dose at 5:00 pm along with dinner), I would think the Lantus is gone as well. Should we consider adding a small quantity of Humalog? (In fact, at the end of last week’s 7:00 pm game, her blood sugar was 325 mg/dl [18.1 mmol/L]).

Your new routine is quite similar to your previous Regular and NPH routine, with regard to making adjustments for exercise, and you are on the right track with frequent monitoring of blood sugar in an attempt to assess a pattern. Good work!

Lantus (insulin glargine) is a once-daily basal insulin intended to provide background insulin requirements for approximately 24 hours. In comparison to NPH, Lantus is essentially peakless in its absorption and bioavailability. Because Lantus is new to those of us in the US, we don’t yet have a lot of clinical experience with it. Aventis Pharmaceuticals, the makers of Lantus, inform me that there are no clinical data available at this time regarding the effect of Lantus during exercise.

Talk to your diabetes team for guidelines on making adjustments for exercise with both the Lantus and Humalog dosages. Humalog dosages at meal times prior to planned exercise may be lowered to allow for slightly higher postprandial/pre-exercise blood sugars. Be aware that Humalog’s action may extend out as long as four hours from injection. The basal insulin (Lantus) may be lowered as well on exercise days. The Lantus at the appropriate dosage does provide the background circulating insulin that your daughter needs to control blood sugar in the fasting, non-active state. The Humalog is intended to be the bolus insulin to cover the carbs at mealtime. With Lantus, (similar to an insulin pump) Humalog coverage for snacks may be necessary unless the Lantus dosage has provided for that. Check this detail of your plan with your diabetes team. Including a good source of protein in meals and snacks on the day of exercise may assist in providing a boost in blood sugar to prevent the lows. You may find the medical nutrition bars containing corn starch such as Extend Bars to be a help on exercise days as well. Discuss the possibility of use with your diabetes team and/or dietitian.

You don’t say what your daughter’s blood sugars were prior to and during her 7:00 pm game, or whether she ingested carbs before or during. If the highs after evening exercise continue to be a pattern, I would first look at snack and previous meal content and their effects on blood sugar. Does a similar rise occur at this time on days that she does not exercise?

There is some individual variation in duration of action of Lantus, and so it may be true that you are observing a tapering of its effect with the rise in blood sugar. If this is the case, an adjustment to her dinner Humalog (or even the addition of a small amount of Regular to her dinner injection) may be enough to carry her through and prevent the highs post exercise. Further blood sugar patterning is necessary with your daughter’s new routine before any conclusions can be made.

Continue the excellent work you are doing with blood sugar monitoring and work closely with her diabetes team to fine tune her regimen.

DMW