Sunday, June 03, 2007

116 miles

This was our last monster weekend, with a 3500 yard swim yesterday morning, followed by a 120-mile bike ride. We started in San Francisco and rode up north into Marin County to the Point Reyes Lighthouse, seen down the stairs in this cell phone camera shot. After riding 58 very hilly miles to get there, I thought I might as well gather some proof that I made it.

I am happy to report that I felt great throughout the whole ride, with the exception of about 10-15 minutes. It has surprised me how quickly the body adapts to riding this longer distance. Our first 100-miler was not really that long ago, and I have felt stronger with each passing week.

During my swim yesterday, I was worried about falling low, which happened earlier this week while swimming (37--yikes!). Mid-swim I ate an extra gel, which, in the end proved to be unnecessary. My BG was >250 when I got out of the water. Why didn't I just test my BG before eating the gel, you may ask? Simply, it is inconvenient, especially during swimming, and I usually don't fall low while in the pool. I hate to miss part of the set because I have to get out of the pool to test! (It's not as bad as getting passed by people I just passed while testing my blood sugar on the bike!) I ate one banana (and bolused) after the swim and started riding about an hour later. At this point my BG was around 300 but I thought it would come down with the bolus for the banana as soon as I started moving. Not so! It was still on the rise. I had to take a bigger correction about an hour later, which finally got things to more reasonable levels. I was a little concerned that my infusion set was bad, but had some syringes and insulin on hand, which I used. (I really hate low BG while exercising and will do a lot to avoid it, including erring on the side of high BG's. I hate being high, too, because I know that it also impairs my performance and messes with my hydration/nutrition in a big way.)

The correction boluses had added up to about 2 units, which is about the total amount of bolusing I normally use for an entire ride's worth of food, so I held off on taking any additional insulin. I have decided that conditions are usually too variable for me to be able to plan ahead much. My general guiding principle is now to take make small adjustments and wait and see what happens, and to keep in mind the total insulin on board (see Amy T's recent post on that subject). Then balance the need for food, trying to avoid depriving myself of food for BG's sake, with insulin boluses of 0.5 U at most. And when things are falling quickly and I'm below 110 or so, suspend the pump completely (as in zero basal rate) and eat until things are more stable. Also, I'm really liking my exercise basal rate profile, which is as follows:
  • 12:00 AM 0.525 U/hr (normal rate)
  • 1:30 AM 0.55 U/hr (normal rate)
  • 7:00 AM 0.4 U/hr (reduced from 0.55; I change this back to its normal value depending on when I start exercising. Currently, I leave it at its normal rate until I start exercising, but depending on how my BG's are acting, I could reduce it early.)
  • 9:00 AM 0.3 U/hr (reduced from 0.35)
  • 1:00 PM 0.175 U/hr (reduced from 0.25; start tapering basal rate assuming I started exercising sometime around 7 or 8 AM)
  • 1:30 PM 0.15 U/hr (reduced from 0.25)
  • 2:30 PM 0.1 U/hr (reduced from 0.25)
  • 3:00 PM 0.05 U/hr (reduced from 0.25; by this point in my exercise, I want very minimal insulin floating around and will fine-tune levels with boluses without worrying too much about accumulating basal insulin)
  • 9:30 PM 0.2 U/hr (reduced from 0.3)
As soon as the exercise is over, I just switch it back to my normal basal rates. In case I am totally spaced out, though, it does go back up to 0.2 U/hr at 9:30 PM. I chose this time because I am planning to use this basal rate profile for the Ironman race, which I am hoping to finish by around 9 PM. (It starts at 7 AM...)


Linda said...

It's always so amazing to read your posts. Good luck at Coeur d'Alene.

Love, Dad.

oreomike said...

I saw a post from last year about using a CGMS.

Do you still? I getting into cycling and have been toying with the idea (I don't think it'll be covered by ins)

Anne said...

hey mike, or oreomike, :)

Yes I still use the CGMS (Dexcom). I stopped using it for a couple months but sprung for some new sensors recently. It has been pretty helpful on my last few rides. It is not totally reliable, but when it works well, I love it, especially on the longer rides.

I'm going to put up a post on my last weekend's training once I have a few minutes.

I think the sensors for Dexcom are better now than when I first started. I've had a bit more success lately. Although, they don't seem to work as well in race conditions, which are usually hotter and more hectic. I don't know why that should make a difference.