Monday, May 11, 2015

Our diabetic control super-weapon

I've received a few questions about the level of control Max typically achieves and how we have been able to keep a relatively low HbA1c in a growing teen. To be honest, this is not always easy and I am far from sure we'll be able to keep him as well controlled over the years.

Pump or MDI?

People frequently assume we are on a pump and some have asked for fine tuning tips. In fact, we are on MDI, 4 to 5 injections a day, depending on the circumstances. We use Novorapid and either Lantus or Levemir. Our slow acting/fast acting insulin schema is slightly unusual (we rely a lot on slow acting insulin and we use asymmetric night/day doses when we split) but I won't comment about it in details here as it could be mistaken for medical advice. I don't think the delivery method matters tremendously and we'd probably keep the same strategy if we were on a pump.

Other drugs? Special diet? Wonder food?

Do we use other drugs? Negative. Specifically, we don't use SGLT-2 inhibitors such as Farxiga or Invokana. There seems to be a growing trend of using these molecules in Type 1 diabetics nowadays but, one one hand, we don't need them and, on the other hand, if there's anything I remember from Med school, it is that caution almost never hurts, especially with kids and growing teens.

[UPDATE 16/05/2015] Well, that wasn't long: the FDA has just released a warning about SGLT-2 inhibitors.

Our diet? Standard, but gluten free as Max has been a celiac for 11 years. One of the problems with Gluten Free food is that, were it not for the lack of gluten, it would definitely be trash food. Are we a LCHF family? Nope. Are we constantly hooked on our Nightscout portal, fine tuning everything and generally behaving like helicopter PITA? Not really. NS and xdrip are wonderful tools, but they are tools and, just as you don't always walk with a multimeter, we don't always need/use them.

And obviously, no cinnamon or fancy tropical berries...

#1 Secret Weapon - the ergometric bike.

Here's a typical late afternoon situation. Max over-corrects an impending low (or, more correctly, enjoys a carb heavy late afternoon snack). We could lament, inject a Insulin correction dose, wait 30 minutes for it to start acting and, keep it in mind for the next 3-4 hours in order to avoid stacking mistakes/complications.

But we don't do that and here is the solution: our exercise bikes. If we were allowed to keep one thing in addition to insulin, we'd keep our bike (and, yes, drop the CGM). With a consistent (typically flywheel + magnetic brake) exercise bike, we have been able to correct almost every situation by short periods of low wattage aerobic exercise from 5 to 20 minutes long. In the above case, Max pedaled for 12 minutes at 50 watts a bit before 6PM.

Some important points to keep in mind.
  • provided you have some insulin on board, you should be able to correct many situations without an insulin injection.
  • you want to keep the exercise 100% aerobic. Any excessive or stressful effort will lead to increased glucose levels through the release of adrenalin, steroids and growth hormone.
  • you don't want to push it too far and end up with a delayed hypoglycemia. Start by small rides and keep note of the wattage and duration. 
  • we use exercise to control "going high" situations, if you have been above 250/300 mg/dL for a while, the metabolic rules of exercise change. Do not exercise until you are back down into that range and have tested that your ketones are negative.

Less secret, less controllable weapon - the treadmill 

The treadmill is typically a bit (or much) harder to adjust precisely. You are generally going to drop, sometimes more quickly, but not always. I believe it is much harder to keep running totally aerobic and stress free. Your mileage may vary.

In addition to the lack of fine control we regularly observe rebound effects post exercise.

If we didn't have a bike, we'd try brisk walking, not running, on the treadmill.

Here's a trace of a recent high we managed to correct by running. The starting conditions were a bit different in this case in the sense that the late afternoon snack was a mid afternoon snack. That means that, if we had overshot the correction, we could have added a few carbs before the evening meal.

In fact, we did correct a bit right after the exercise ended. While we started with an accurate CGM, the BG Meter test at 107 mg/dL clearly indicates we were going down a bit too quickly. The G4 (non AP) algorithm would have informed us of that fall with a 15-20 min delay, at which point it would have been too late. With a bit of experience, we managed a soft landing.

I guess that the key point here is that you don't automatically have to correct a high with an insulin bolus. 5 to 10 minutes can control a lot of situations that may otherwise have been controlled by an additional injection and a long wait in front of the TV....

Good exercise bikes are compact, almost silent and relatively cheap. On our opinion, the best diabetes management tool investment we ever made.

If you are interested, a recent review of the exercise and diabetes literature can be found here: Advances in Exercise, Physical Activity, and Diabetes Mellitus. This article confirms that the optimal time/benefit activity is the ergometric bike.  However, for other purposes, it is again somewhat depressing: very small sample sizes, very mild exercise. As if active T1D diabetics were rare and extremely fragile...

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