Anyone still here? Control IQ and exercise (part 1)

Hi. It's been awhile. Do people still read blogs? (I think I know the answer.) A lot has happened since I last wrote here, but I thought I would drop in to say that I am currently using a Tandem tslim:X2 pump with the Dexcom G6 CGM and the Tandem Control IQ ("CIQ") algorithm. I have been playing around a lot with the exercise mode and cycling and am finally getting something to work well. It took a lot of trial and error, and I got some really great help from some Facebook groups; but otherwise I felt like I was on my own figuring this out. Hopefully others can skip ahead past some of the stuff I tried. (Mostly, using my regular profiles in exercise mode did not work well for me for any exercise over an hour.)

I generally bike a minimum of 90 minutes nearly every day and have been on rides recently up to about 7 hours. The intensity varies quite a bit since I am sometimes working on intervals, often climbing and also often descending back down those climbs. My goal is to use the exercise mode with no lows or near lows, no serious or prolonged highs, and the ability to fuel my exercise rather than my blood sugar.

**Note! I am not a doctor! While I feel confident adjusting my pump settings, and my endocrinologist has basically said, "Why are you asking me? You know how to figure it out," please do not interpret this post as medical or insulin dosing advice. Check in with your doctor, please.**

The short story is that I created a cycling profile with sensitivity factors 2.5 to 3.5 times my normal settings, increasing every hour or two over a period of about 6 hours. So, for example, instead of 1:55, I am using 1:170 for the first hour. My basal rates stay about the same initially, since I tend to spike during the first hour, and then taper every hour or two. I can then allow the CIQ algorithm to automatically adjust basals and give correction boluses without messing around with it too much, but also eat when I need to. Initially I was taking a small 0.05 unit bolus to prevent CIQ from auto-bolusing, but this is hard to remember to do for longer rides, and I do want to be able to prevent highs as well. I turn on the profile and exercise mode right before I head out, because I also eat a small snack (about 11 g carbs) and tend to go high in the first hour.

I have modified my on-bike food to include foods with a bit of protein and fat, but still pack a ton of gels to bring me out of lows should I encounter them. FWIW if I ever get a hunger pang during a ride, it almost always is a precursor to falling BGs.

A recent ride beginning 6 AM and ending around 11. I ate about 100 cals/hour. Ride included 3 50-minute mountain climbs.

Twenty-Five Years

Twenty-five years ago, today, I was pulled from my gym class in my freshman year of high school for a trip to the hospital that would quickly result in a diagnosis of type 1 diabetes.  I had recently turned 14 and had been noticing some of the signs.  I even joked with my best friend Libby that I "must have diabetes or something" because of my unquenchable thirst and frequent trips to the bathroom.  One night after a pizza party, I stepped on the scale and noticed that I weighed less than before dinner.  In youthful optimism and a sign of some probably unhealthy thinking about body image, I was excited about the weight loss and had bought a bunch of new school clothes for my too-skinny body.  My dad, who was diagnosed with type 1 diabetes as an adult, had tested my blood glucose the night before.  Somehow my parents shielded me from the worry that must have hit them hard at the high reading; or perhaps they were hoping against hope that it was somehow a fluke.  When I asked the nurse at the hospital, "Do I have diabetes?" she looked at me in some surprise and said something to the effect of "Yes, of course."  Oh.

I received the necessary education and tools and had the support of my dad and the rest of my family and my pediatrician to get my blood sugars better regulated.  I recall not being able to read at first as my eyes adjusted to the normal blood sugars, and asking my 9th grade English teacher (Mrs. Bills) if I could eat a snack during her class.  One time, I told a surprisingly gullible friend that my blood glucose meter lancet was a brain scanner: "you just run it over your head like this." In what I view as a positive point of reflection, I do not recall diabetes playing a major role in my life during the rest of high school.  Perhaps I had a longer honeymoon period?  Or the super-rigid schedule I lived by helped keep things smoother?  I view this time as the easiest period I have had in my life with diabetes.  I joined the cross country team, participated in band and orchestra, continued piano lessons and did well at my academics.  But my diabetes regimen did mean that I never slept in on weekends, and had to arrange special accommodations if I ever wanted to eat dinner at a party that started later than my regular meal time.  And at that time, I absolutely never ate candy or desserts except for perhaps angel food cake on my birthday or to treat a low blood sugar.  I remember saying, "When I am cured, I will eat a doughnut."

I was fortunate to be surrounded by family and friends who did not once question my ability to do whatever I set out to do, whether that was to study hard for school, ride my bike around town or join the cross country team.  I imagine there were some harder moments that I have since forgotten; but overall, I felt like I was doing okay with life.  In the more than 20 years since that time, I have had my ups and downs with diabetes, and it has made for some good stories and some very magical moments.  While having diabetes has certainly made life more difficult in many ways, I am grateful especially for the wonderful people I have met as a result, and the many insights I have been given into my own body. Also I believe that in many ways I may be healthier because of the early focus diabetes brought on my health; for one, I realized right away the positive impact exercise had on my diabetes management, and was more dedicated and consistent with it as a result.  This was actually a gift that I have carried with me throughout my life so far.  Here's hoping to at least another two big twenty-five year milestones down the road.  And I'd like to extend a heartfelt "thank you" to the many friends and family members who have been a source of strength and support to me over these past 25 years.

Sheboygan BGs--Update on My Insulin Tweaks

Dexcom readings around Sheboygan crit

(Update on BGs after major insulin adjustments described in my last post.)  

After a bit of a low BG before going to bed last night, I shut off my pump for an hour, which allowed my BGs to creep up to around 200.  The increased basal rates were a bit too much from about midnight until I woke up, as evidenced by a steady but slow drop between those times; but fortunately I landed in a nice spot this morning, right around 100.  I lowered the early morning basal by 0.1 U/hr so hopefully tonight will be better.

For the rest of the day, things have worked out pretty well.  The first bump on the Dexcom shown here is my breakfast spike, which came down after about a 20 minute warmup.  I saw "86" with a slight downward trend about an hour before the race start, and still had my basals cranked up, so ate a granola bar.  I warmed up a little longer and then headed for the car once it started raining about 40 minutes before the start.  My last BG check before the race showed about 135 and the Dexcom showed a flat trend at 120.  Finally things seemed to be where I wanted them!  I was a little anxious, actually, about having a normal BG, and popped a couple Dex 4 glucose tabs just in case.

The rain began in a complete downpour and I was soaked just waiting on the line. The field quickly became strung out and I was somewhere in the middle (I think), tucking in behind people when I could.  One of the biggest puddles on the course was right in the corner, but I actually enjoyed plowing through the water--at least it wasn't cold!  After the race, I was elated to learn that my teammate, Becca Schepps, had won the race!  I knew she was strong enough and had the tactical skills to do it, so was glad that it worked out! Very exciting.

Once I had changed out of my sopping clothes, I checked my BG and came in at 115, although I felt more like 60.  If the race had been much longer, I think I would have gone low (perhaps)? I think that I might either bring my race basal down a little, or eat a little more before if I find myself in the same position tomorrow.  I'd rather be up a little at the finish just to be on the safe side. I bolused a huge amount (compared to normal) for lunch and then corrected for the high (seen as the excursion above the line) and have been satisfied with how things are continuing to work out.

Although this game never ends, I am glad to have tamped down some of the constant highs and BG spikes.  Tomorrow we race in Fond du Lac, and I am hoping for similarly good BGs but a race without rain!

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 Few Requests (Short of a Cure)

"I'm melting!"

When I was in college, two days before my first marathon, I capsized while sailing in the Charles River.  I blame my "date" who told me he sailed every summer growing up.  That seemed likely until he pulled the sail in tight, and didn't then release it when we were jibing in a strong wind.  End of story.  The boat house folks sent out a canoe for the sailboat but nothing for us.  After swimming to shore, I pulled out my pump, securely water-proofed in a few ziplocs, held it up and watched the water drain onto the ground. Oh no.  For my first marathon, I was back on injections for the first time in more than a year.  After then, I would have dreams where I was swimming or otherwise submersed in water and I would be holding the pump above the water, frantic that it might get wet. I felt like one of the witches in Oz.  Once I finally was able to switch to a waterproof pump, those dreams went away.  The development of water-proof insulin pumps is one of the advances that has made a significant, positive impact on my life--not just in getting rid of my pump-drowning dreams, but allowing me to stay connected during years of swimming and competing in triathlon.  And I'm no longer afraid of the rain.

But wait.  I have more requests.  Short of a cure, here are a few things on my diabetes wish list:

1) Blood insulin meter.  Let's say it's been 2 hours since my injection and I'm about to go exercise.  Wouldn't it be handy to just be able to know how much insulin is really still active?  Or how about when my blood sugar is 400 and I take a huge bolus to correct and two hours later I'm still at 400.  What happened to all that insulin?  Is it just hanging out, waiting to crush me later?  How could I know? Bolus up, maybe do a super bolus, and hope for the best!  Or be conservative and watch the BG hover up there for hours.  I imagine the metabolism of insulin varies a lot depending on many factors but no one really seems to discuss this much, probably because we (as patients) have no way to measure it.  And what about being able to pinpoint that the infusion site is bad vs I am coming down with a cold or maybe that day off from exercise is affecting me more than I expected.  So many variables! This could help significantly to cut down on the guesswork.

2) Stable glucagon in a pen delivery device.  One of those glucagon kits is $100 and can't really be used more than once according to enclosed instructions.  Sure it's easy to eat food and doesn't require an injection.  But seriously, I don't care about injections.  Those pen injectors are pretty slick.  What I want is good glucose control and to not have to eat 500 calories in a day to treat a low.  I don't want to go drink some soda after I overestimated the carbs in a filling meal.  I just don't want to HAVE to eat.  Especially after I just brushed my teeth for the 3rd time. Maybe it sounds petty to some people but I just wish I didn't have to make food and carbs such a focus of my life.  Let me introduce a little distance between food as nourishment and food as the thing that makes all my crappy feelings (i.e., hypoglycemia) go away.

3) Data integration with non-diabetes devices. FREE THE DATA!  Free it! Do it! Do it now!! Hey diabetes technology people!  Hey FDA! Design your devices so they are safe but let us capture the data in a way that we can use how we want!  I am not a moron!  This is perhaps the thing that drives me the most nuts.  There is absolutely no reason technology-wise that the continuous glucose meter data, for example, should be restricted from streaming to my iPhone or workout device. Arghhh! I have to stop writing about it because it is so incredibly frustrating.  I know there is a lot of work on this but there shouldn't have to be any.  Free the data and people will design apps.  FDA are you listening?!

Okay, those three things are probably enough for now.  If the list is too daunting, let's just get that cure all sorted out. Thanks!

Twenty-two years

Twenty-two years ago today, I was pulled from 9th grade gym class at Highland High School and made my way to Primary Children's Hospital in Salt Lake City, where I was diagnosed with type 1 diabetes.  I started using Regular and NPH insulin and learned how to test my blood sugar on an early model One Touch meter.  It took me fifteen minutes to poke my finger the first time.  I continued on the cross country team and since then I have run twelve marathons, qualified for and run the Boston Marathon, completed four Ironman triathlons, and competed in about 30 road bike races.  I would give anything to be able to go just one mile without diabetes.  Today I am raising money for a cure for type 1 diabetes with the JDRF for all of us with type 1 diabetes and in honor of those who have been taken from us too soon.  Please donate generously if you are able; any amount is welcome.  Donations can be made at my page at http://ride.jdrf.org/rider.cfm?id=9740.

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!