Human Guinea Pig
Since the Olympics I have been formulating a plan to prepare my insulin dosing stategy for 30k and 50k races. I decided that the best way to do this was to do four to five time-trials over the course of the off-season. The first timetrial was two days ago in Bend Oregon. I set my basal insulin at my current resting rate which is .5 units per hour. For reference the basal rate I used at the Olympics was 2 units per hour, or four times the dose I just tested. I planned to ski 30k with the first 20k at just above threshold with maximal effort over the last 10k. The effort I put in was reflected by my lactates. My heart-rates were very low due to suppression from heavy training. My hypothesis was that my blood glucose would remain constant for the first 20k and then rise over the last 10k due to the anaerobic nature of a maximal effort. To my surprise my glucose remained constant throughout the effort. I fed an average of 10 ounces of Gatorade per 5ks. Throughout the test I also compared the data that my new continuous glucose monitor (cgm) gave me to the results I got from my blood testing Lifescan glucose monitor. The numbers were close enough that I am now confident in the use of the cgm during races. All of the data from the test can be found below.
I skied thee 7k loops followed by four 3k loops. I stopped at the end of each loop for blood testing.
May 31, 2010 Bend, Oregon
44 F, Light rain
30km Pursuit TT
KM, Time In, Time out, Split, HR, CGM, BG, Lactate, Feed
Start 106, 100
7km, 18.11 19.41, 18.11, 146, 88, 105, 5.6, 10 oz
14km, 37.11 39.12, 17.30, 155, 84, 119, 6.7, 11 oz
21km, 57.01 58.31, 17.39, 152, 96, 107, 5.8, 5 oz
24km, 1.06.30 1.08.06, 7.59, 155, 89, 108, 9.0, 7 oz
27km, 1.15.23 1.16.50, 7.17, 156, 96, 112, 8.9, 12 oz
30km, 1.24.26 1.25.56, 7.36, 157, 100 100, 9.1, 12 oz
33km, 1.33.17 7.21, 160, 105 125, 10.3
Switched to skate at 14km