As a diabetic, balancing my blood sugar during races is critical for a good performance. This is a difficult task given the numerous factors that can affect glucose in the blood stream. For this post I am only going to focus on one such factor. .. terrain.
Through extensive testing I have learned that when I am in an anaerobic state my glucose rises significantly. When I am in an aerobic state my glucose drops. The rate that it drops increases with the intenisty of the effort. I am at peak sugar burning mode at threshold. Once my heartrate climbs into level 4 and level 5 territory my glucose suddenly begins to rise.
In a normal ski race I am constantly bouncing between a threshold effort and maximal effort. My heartrate peaks at the top of a hill and slows as I go down the other side. Thus my glucose levels rise and fall throughout the race until I put in a final anaerobic surge over the last few kilometers of a race. A normal glucose level for a non-diabetic ranges from 70-140 during a race. At below 70 a racer would be experiencing a “bonk.” So it is important that I do not use too much insulin during a race. However it is just as important that I do not use too little insulin. My lactate level starts to rise unnaturally when my sugar reaches a level of 240 or more. The margin for error is small, but thanks to testing on the Center of Excellence treadmill and many races and timetrials I have developed an inuslin dosing strategy that generally gives me a glucose level of 160 at the finish of a 15k race.
There are two types of insulin dosing, basal and bolus. Insulin is delivered in measurements called units. A basal insulin is a constant drip that is delivered into my bloodstream 24 hours a day by a mechanical box called an insulin pump. The pump I use is called an OmniPod. The bolus insulin is also delivered by the pump and is given at meal times or at any time a significant amount of carb is consumed. I progam the pump and override the program when need be. It is not an automated devise.
My basal rate depends on many different factors that I am not going to go into in this article, but for reference lets assume that I am using my most commom basal dose of .7 units per hour in the days leading up to a ski race. My pre-race dosing strategybegins 1.5 hours before the start. At this point I double my normal basal insulin dose to 1.5 units per hour. Twenty minutes before the start I bring the basal rate up to 5 units per hour. I keep the basal rate at 5 units per hour until the completion of the race.
Yesterday’s Race to the Castle on Whiteface and other hill-climb timetrials present a different challenge for me. Because there is no significant terrain variation there is no place to recover. I am in an anaerobic state for over 50% of the race. Thus my bloodsugar constantly rises unless I take even more insulin than in a conventional race. During yesterday’s race my non-racing basal rate was .5 units per hour. During the race I increased my basal rate to 7 units per hour and I still finished the race witha a relatively high glucose level of 204. I have not documented any ill affects from racing at this glucose level but there is definately room for improvement in my controlm durin hill climbs.