Posted by on Tuesday 18 December 2018

Rage Bolus - a Christmas classic

Disney Pixar's Inside Out. One of my absolute favourite films.
I've seen a few things about rage boluses in recent months and it did that rare thing of making me think, "I should write a post about that".

I can't remember exactly when I first came across the term 'rage bolus', but I think it was quite soon after discovering of the power of peer support and shared experience. I am almost certain that it came from that most legengary of #DOC legends, Kerri Molone Sparling's Six Until Me, and I'm pretty sure that it was Kerri who came up with the phrase originally.

If you live with diabetes and use insulin, even if you've never heard it before, you will instantly know exactly what is meant by a rage bolus. It was phrase that made me go, "Aha! Yes!! I know that thing." Type 1 diabetes can be incredibly frustrating to live with. For all the illusion of 'diabetes maths', and there is no question that sometimes carb ratios and insulin sensitivity factors can and do work (some days / most of the time / once in a blue moon), it is also absolutely the case that there's a lot more going on than food + dose = reliable results. And when things go a bit off track you can feel that you have got it wrong (and sometimes you have!). A sense of personal failure. Feeling like an idiot. So frustrating. Other times you know that you have done all the things you are supposed to do (scrupulously counted carbs in a carefully chosen, healthy meal that you've eaten many times before with reliable results) and still your BG ends up in chaos. Doubly frustrating. Or you just decided to treat yourself (after all everyone else with their functioning pancreases and none of this to worry about were having a lovely time) and then you see it all coming back to slap you in the face, even though you tried your best to work it out. Triply frustrating.

Sometimes there are only so many small, carefully-calculated, properly-spaced correction doses you can try and wait grinding your teeth and stewing in double figures for hours (or days) willing your BGs to stop inexorably rising or stubbornly unmoved before you go OH FOR GOODNESS SAKE and whack in a big ole slosh of insulin to try to get things moving downwards.

And as we approach Christmas I am aware that we are heading into 'rage bolus' season. Meals are likely to be less predictable. Less easily guessed or measured. You may have a little sniffle, or be drinking sugary alcohol, be surrounded by endless nibbles, or be less active than usual, or exposed to any number of other factors that might make decent dose-guesswork much harder.

Let me just be perfectly clear about this - rage boluses are generally a terrible idea. They almost always result in hypoglycaemia, sometimes in a really nasty and stubborn and/or scary low. And crashing from one out of range BG to another at the other end of the scale is likely to make you feel even more frustrated, annoyed and difficult to live with.

So why do we do it to ourselves?

Because, frankly, sometimes it WORKS. And like an addicted gambler feeding endless coins into our BGs fixed-odds betting terminal we have reached the end of balanced and logical assessment of likely outcomes. Sometimes high BGs are the result of a significant underestimation of carbs. Or perhaps it's a dose that hasn't absorbed properly. There are circumstances where we are in 'insulin deficit' of a number of units. And where the food already eaten is still feeding glucose into the bloodstream, and where a dose isn't likely to reach maximum effect until an hour after you grit your teeth and go for it, there can be long, long hours between a measured, cautious correction dose and seeing any effect at all.

Repeatedly, I have heard respected diabetes clinicians suggest that one of the reasons that rage boluses are a bad idea is that taking more insulin doesn't make it act more quickly, it only makes you fall further in the end which leads to likely hypoglycaemia. I think it would be much easier to resist the rage bolus urge if this was actually true. The simple, demonstrable fact is that taking a larger BG correction does make it act faster to reduce high BGs. We know this because we see it happen. And to pretend that it doesn't really isn't going to help me in a consultation. If I take a 0.5u correction dose (as suggested by my pump or smart meter) then after a reasonably predictable onset time I will have a proportion of that 0.5u available to act on my errant BG. If I take a 5u correction, after the same onset time I will have much more circulating insulin available. It may not be exactly mathematically 10x as much, but it will be more. And If I've rage-bolused before and checked after 30 minutes, then an hour, an hour and a half... I will have seen this happen.

Rage boluses do reduce high BG faster.

It's just that they also add chaos onto more chaos.

Sometimes I will make this calculation in my head:

OK so I've currently got annoyingly high BG. I also have some insulin already on board. Along with that, I also have half a meal which I may (or may not) have hoplessly inaccurately estimated that is feeding more glucose in. Some of which will be accounted for by the dose that's already acting. Or possibly it won't. Solution? I'll dose a big ole slug of insulin in now to get things moving in the right direction over the next 2 hours, then depending on how things go I will eat some extra carbs later on to mop up the last bits of the dose.

I mean... what could possibly go wrong?

I once referred to this frustrated act-and-counteract ballet as uncertainty tennis (particularly where my guesses and second-guesses follow in double-quick time and everything overlaps far more quickly that it can possibly have had enough time to actually take effect).

Try to give yourself some head-space this Christmas. Give yourself a little more leeway. Perfection is an illusion. BG perfection doubly so. No one wants to live with a grumpy pancreas-impersonater muttering and grumbling after every meal.

And if possible try to resist the rage bolus urge. Except for the times when it works perfectly and brings you back neatly into mid-range. I mean... those are just awesome! (and incredibly unlikely)


  1. So it is basicaly the same as hypo overcompensation/overtreatment with too much carbs, which ends in hyper... Just from the opposite side of spectrum... 😉

  2. Hi Mike,

    A brilliant post, as always :)

    I hope you had a wonderful Christmas and didn't have to 'rage bolus' at all this year.

    Our Golden Retriever, Elsi, ended up having a lot more walks than usual to bring the BGs down after all the carby goodies - particularly the Christmas pudding and Yule log :)

    She was a superstar, always with a wagging tail :)

    You're spot on about the faster onset time with bigger boluses - this holds true for practically all drugs given subcutaneously. But as you've pointed out, once you've injected what is effectively an overdose, you can't get any of it back. Which will lead to real hypo problems without keeping a hawk eye on it.

    This is a similar article by the author of Think Like a Pancreas' called 'Put Some Muscle in Your Insulin':

    I prefer to use the synergy of activity and a small RAI bolus to bring the BGs back into range though.

    Hats off to everybody who manages T1D without a CGM - there are just too many (often unmeasurable and changeable) factors to account for.

    With very best wishes,


  3. Protip: never rage bolus in the evening.

    Why no, there is no special reason I am awake at 4:00 am, why do you ask?