Adjusting Type 1 Diabetes to Racing Tour of America's Dairyland

Often when I travel, it seems like I need to increase my insulin basal rates; but racing this week in Wisconsin has required a surprisingly large adjustment.  Leading up to the start of the series for me, I had my basal rates on increased, "taper" mode, which is what I try to remember to use when I have a rest week in my training, or am tapering my training before a race.  (With a decreased training load, I will need more insulin.)  After arriving in Wisconsin for my first race (Friday),  I turned on my "race day" basal rate profile.  This profile has an approximate 30% increase an hour before my planned breakfast and throughout my races, which are all 30-40 minutes in length, beginning sometime between 11:20 and 11:50 AM.  At other times, the basal rate profile uses my normal rates.  At my race Sunday in Waukesha, my BG started around 190 and ended up around 300 forty minutes later.  I don't necessarily expect to have a flat line (BG-wise) during a race, so my goal is to start lower so that I don't finish the race quite so high.

Aside from the race-related BG spikes, I have had overall higher BGs, frustratingly resistant to multiple corrections.  Leaving my race day basal rate profile on constantly was still not bringing my BGs down so yesterday afternoon I just decided to increase my basal rates by another 30% or so.  Overnight, things were a bit better and this morning, I programmed a new basal rate profile that is 30% higher than my already high, "taper" profile.  I looked back and saw that, instead of my typical total daily insulin dose of 20-32 units, I was needing more than 40 units for consecutive days, which is very much outside the norm for me.  Since I had been staying high after meals and my corrections were not working well, I also reprogrammed my carb ratios from 15 g/U to 11 g/U and lowered all of my correction factors by 10 mg/dL/U.

It has seemed a bit paradoxical that during an 10-day race series (with 8 races), I would need so much more insulin.  But, perhaps it makes sense.  Although I am racing almost daily, the races are short & intense.  My blood sugar always goes up during 30-40 min crits, which are high-adrenalin events.  The common thought is that, with high intensity activities, adrenalin is released, causing the liver to release glucose from glycogen stores; for someone with diabetes, the lack of a normal insulin response can easily leave the blood sugar high.  Furthermore, the short duration of these crits means that my overall exercise volume is much lower.  And to compound that, we spend most of the rest of race days resting or doing light activity, which is in contrast to a more typical day of traveling (by foot or bike) to and from work, working a full day, etc.

So far, during our rest day today, I have only had a couple brief excursions over 200, which is a huge improvement over the past few days.  It is always nerve-wracking to take so much more insulin, but it seems to be working well so far.  But really--since when did I have to take 1.4 units for an apple?  We will resume racing tomorrow and continue through Sunday if all goes well, and I fully expect that I will have to make more adjustments.  Diabetes is always a work-in-progress!

Total daily rapid-acting insulin using Omnipod

June 12--end of 18-hr training week; June 13--begin taper; 

June 17--daily racing begins; June 20--no race

Total Daily Insulin Versus Cycling Time

Thanks to my super-fantastic coach and team director Kori, I have been logging my workouts since she started working with me late last year.  From my insulin pump, I can also pull off my total daily insulin amounts (or "TDD" for total daily dose) since the beginning of time, give or take.  I thought it might be fun to just plot out my TDD as a function of my cycling time, even though the results are probably as shocking as showing that washing hands reduces the spread of colds.  Anyway, I decided to just do a very simple linear regression of the data between January and March, 2011.  This model ignores variables such as what other exercise I did that day (I often walk about 40 minutes per day), whether I ate more or less than normal, my weight, how old my infusion set was, etc.  In short, the only variable I am considering is time on the bike.  But there still is a clear trend that shows with increasing time on the bike, I took less insulin.

An Overly Simplistic Model But Still Sort of Interesting

For those who like details, the slope was -0.046 U/min, the y-intercept was 35.3 U and correlation coefficient was -0.65.  If I included only March, rather than January through March, the correlation coefficient was -0.68.  The mean TDD for January was 32 U and was 30 U for March.  Total cycling time was only 90 minutes more in March although the intensity was higher.  My weight was about 5 pounds less in March.  Again, one of the most important and obvious variables affecting TDD is calorie intake, which is not included here.  But still it was fun to plot this out since the data was readily available.   Maybe I will be better about logging total activity time, including other forms of exercise, for a period of time.  If I am super motivated, I might even track calories although I can only stand doing that once in a while.

A Role for Leptin in Type 1 Diabetes?

While glancing over today's science headlines, I noticed a write-up in Science Daily of a study from UT Southwestern Medical Center involving the administration of recombinant leptin (Amlylin Pharmaceuticals) to non-obese mice (which serve as a model for human type 1 diabetes).  Treating the mice with leptin alone, the researchers saw a return from a ketogenic state and a normalization of blood sugar levels, as evidenced by a normalized HbA1c.  They postulate that leptin mediates this effect by suppressing glucagon and therefore glucose production via glycogen breakdown in the liver.  The most exciting aspect of the study to me was that the improvement in blood glucose levels was not accompanied by the wild variability that people with type 1 diabetes deal with daily.  There were also improvements seen in lipid profiles and other biomarkers related to complications of type 1 diabetes--heart disease, in particular.  While insulin is a hormone that enhances fat storage (lipogenesis), leptin works in an opposing manner, suppressing lipogenesis.  Another effect of treatment with leptin was that the mice returned to a normal weight (vs those on "insulin monotherapy"). The authors found that a combination of leptin and a low dose of insulin led to significant improvements in blood glucose levels as well as in other metabolic markers. 

While I still maintain my wait-and-see approach--after all, how many times has the NOD mouse been cured?--this seems like one of the more interesting research headlines I've seen in a while.  There are some questions I have, such as whether leptin regulation is actually impaired in type 1 diabetes, and if additional administration could have unanticipated consequences.  After all, it clearly is potently bioactive.  Another huge caveat is that the mice started with very low blood leptin levels because they had a depletion of fat due to an initial state of uncontrolled diabetes.  So it is unknown whether leptin would have as strong of an effect in humans with type 1.  Still, I hope that clinical trials are already well into the planning stages.  It seems like a worthwhile avenue of pursuit.  Read the original study at PNAS for the many details that I have missed!

How's Your Humalog?

Has anyone noticed a recent change in the way your Humalog is being absorbed? Or has anyone had a change in the way your Humalog is absorbed over some period of time? Of course there are a million explanations for anything in diabetes but Humalog just doesn't seem to be working for me the way it used to--it takes a very long time to start acting (at least an hour usually) and seems to accumulate and then hit me later on in the day (by pump or by injection). I assume it's just me but I've had one other friend report the same thing in the past few weeks. I've used Lilly insulin since day 1 and it has been great but I am considering switching over to Novolog or Apidra. I've tried to rule out all of the usual suspects (pump problems, stress etc.) It could also be that I'm paying a lot closer attention so am more finicky about getting rid of those highs.

Next Up... Wildflower Long Course

Well, I pulled the tent out of the closet without too many boxes falling on my head and I found the Thermarest and the most important item for Wildflower: earplugs. I'm doing the Long Course Saturday for the 2nd time and looking forward to relatively moderate temperatures. Nothing will compare with the first year I watched Wildflower when it was well over 100--I was retreating under the shade and I wasn't even competing. I'm looking forward to meeting up with Bill C. and Peter N. and teammates on my tri team. I don't know how many athletes there are but it is in the thousands and it is one huge camping party--with the exception that most people will be in bed nice & early on Friday night.

I'm not sure if I'll go with the Levemir that I've been using or get back on my pump or do some combination; in the spirit of living on the edge, maybe I'll the ignore the (very good) advice, "Nothing new on race day!"