Friday, 6 May 2011


I've started cycling into work again, after a break of over a year, which has led to some interesting things diabetes-wise.

I decided to start cycling again for a few reasons. Mainly, I really missed it. I used to cycle all the time, but then when I was writing up I was just too tired, and then I was ill, and it fell by the wayside. Since we moved to our new place I've been getting the bus, but it's bugged me that I'm then dependent on bus timetables to get anywhere, not to mention the expense. I also need to lose some weight. I'm about a stone heavier than I'd like to be, and I've started making some changes (omg, I love the kinect fitness!), but I figured that cycling eight miles a day has got to be a good addition! I also know that exercise helps my diabetes control. I used to see differences when I wasn't cycling, and I generally used to run with less highs, and needing less insulin when I was cycling.

So, putting all of those things together, and inspired by the lovely weather we've had recently, I finally got my backside in gear, got my bike serviced, figured out the route to work (but still managed to get lost. Twice...), and started cycling again.

I wasn't sure what effect to expect on my BG and insulin levels. I was already cycling when I went onto MDI, and I'd hadn't cycled for a few months when I started on the pump. The upshot being that I knew how to manage cycling on MDI, but that was when I was trying to make lantus work for me when it really didn't match my basal needs. I had no idea how to do it on the pump. In addition, I tend to find that the first few days of any new exercise tends to hit me quite hard, in that I drop through the floor, but then my body adjusts and things even out.

And this is what I saw for the first few days. Even with using 50% basal rates, for up to an hour before the cycle, during, and after, and free carbs, I was still hypoing more often that I'd like. I had a look at my results, and set up a new basal profile (imaginatively entitled 'exercise') which was pretty much just a 25% reduction of my previous basal. That worked, for a day or two, and then my body got over the shock of the cycling, and I started to run high again, so I switched back to the old profile.

At the moment, I'm tending to find that I don't have to change my basal at all to go cycling, which was a surprise. What is an even bigger surprise is what to do about my breakfast bolus. On MDI, I used to reduce my breakfast bolus by 30%, and that seemed to work quite nicely. If I try that on the pump, it keeps me steady during the cycle, but then I rise a couple of hours later. It seems that I need the full bolus, just not all at once. I've been playing about with the extended bolus, and so far 70% up front with the rest over an hour seems to be best. I'm dropping a little before lunch, but I'm starting to suspect that's a basal issue.

The interesting thing is that if I screw up the extension on the bolus (like I did this morning - I tried reducing the bolus by 10%, but then didn't increase the percent up front to keep me steady, so I was high after two hours), and I end up high at the two hour mark, they seem to be fairly stubborn highs. They're not too high - mainly 10/11, but they seem to need more insulin to come down, whereas the same amount of insulin, but given in the right proportions seems to keep me steady. It's been fascinating to see how much being high at that point has an effect on my insulin resistance.

Of course, the other thing is that there are several points in the day now where I'm dropping, and I think I'm now seeing the general effect of consistent exercise on my insulin sensitivity. You know what that means: basal testing. Roll on the sugar free jelly!

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