I hope the following discussion is also interesting for pumpers. It shows a potential new feature and I would like to hear your feedback.
The Insulin On Board (IOB) is a guestimation how many units of insulin are still active from the last shot. Foremost it is a reminder that additional physical activity might amplify these remaining units (risk of lows). In addition to that it helps to prevent the overcorrection of a higher blood glucose.
With physical activity I see the need for an additional reminder: Sensitivity On Board (SOB). After sports the sensitivity to insulin is increased for several hours. The muscles will restore their glycogen stores and this will for sure lower the blood glucose. The timespan depends on the level of activity and individual reactions. For simplification I will adopt the workings of our Glucosurfer project but I think it can be applied to a pump too. In our diary we have four levels of activity: normal, moderate, high and maximum. Let us assume we can define the SOB timespan in minutes for every level.
Now the system would work like this:
You would work out for 1 hour and this will be documented in the diary / pump: high activity starting at time x. Associated with this high level you have defined that high activity leads to an increased sensitivity for 300 minutes (=5 hours). So for the next x+5 hours the SOB warning will be shown. It will remind you that you are now acting under the influence of physical activity that happened hours before. I am not sure if it is wise to use the information to directly reduce the I:C. Maybe the character of a warning would be more appropriate. What do you think?
Yeah, right now, in order to accomodate physical activity, we have to balance carb intake before and after along with basal/bolus before and after.
From a practical standpoint, with a pump given a particular type of activity, I generally will adjust basal rate and keep everything else constant. Or, I'll eat a few carbs to get through a shorter work-out and keep everything else constant.
It would be nice to be able to punch in a BG and anticipated level of activity, maybe a target BG to achieve after certain period of time has passed, and have my pump adjust whatever insulin delivery variable is needed to achieve my target. Even if you can get the algorith to get us in the same ballpark as far as insulin delivery is concerned, with the ability to individualize the program, that would be a huge step forward.
One of the big hurdles is really what you are trying to anticipate, the time variable. Even if we had the perfect pump program, we would still have to account for time of insulin action.
That's one of the advantages of keeping my work-outs reletively short and high intensity. It's a lot easier to eat a load of carbs before a workout and time the BG spike to coincide with peak activity then it is to adjust my basal rate, which may take a couple of hours to kick in and leave me spiking later if I misjudge my dosing.
! have been type 1 for 47 years and currently taking Novolog via Insulin Pump. I also have MS so being active on my feet is tough. I only work Part Time on weekends. Is their any form activity that a type 1 and MS person can do. I can be on my feet for 15 to 20 minutes before balance can be a problem. My A1c in Dec 2011 was 5.9
Hi Bill, I think it is better to ask again in the general forum. There you will get more ideas for your specific problem.