Today we rode from San Francisco, around Tiburon, to Nicasio and towards the lighthouse at Point Reyes and back. The weather was cool and cloudy at first but sunshine broke through for the second half of the ride. I initially felt weak from low BG's last night and especially this morning before the ride, but I felt stronger after about an hour. I used the basal rates shown in the chart and decreased them throughout the ride. I was consistently eating about 300 calories per hour with a slight increase towards the end of the ride. Most interesting to me was how steady my BG was right around 80-100 despite the changing basal rates. And for the second half of the ride, the Dexcom was completely flat. It didn't seem to matter whether I ate something small (chocolate GU at 20 g) or big (40 g of honey fruit snacks). It was almost as if my body wanted to stay right there! But there is a more likely explanation, of course. Initially, when my basal rates were a bit higher (0.7-0.9) I was rising a bit after each snack and then falling again. But when my basal rate was lower at 0.5 for the second half, I stayed pretty steady after eating. So it appears that the glucose entering my blood from the gut was leaving at about the exact same rate there.
The basal rates were a touch too high initially and need some adjusting; however, I want to make sure I don't start off high, since it seems to make things much more difficult to manage overall.
The ride was a great confidence-booster for Ironman Coeur d'Alene, which is approaching quickly!