Will work differentlly in everyone. The way to test it, once basals are
right, is to give an adjustment and test hourly for the next 4 hours.
You can then work out the percentage of the total drop for each hour.
No insulin kicks in after 5 mins. Novo kicks in a bitter quicker than
Humalog (in our expereince) but took longer to leave the system.. sometimes
up to 5 hours, peaking at about 90mins from bolus. Humalog takes a little
longer to kick in, but has a higher peak and tends to compeltely leave after
4 hours max.
We use the following to calculate IOB based on how Humalog works for Sarah
using her tummy, there's a small delay if sites are in her butt.
30 mins: 90% IOB
60 mins 70%
90 mins 50%
I prepared a little chart for Sarah to use at school and always noted the
IOB at mid morning break and gave this to her, based on her breakfast bolus
We are using an Animas 2020 now with an excellent and accurate IOB
calculator. When on the Cozmo and previously the MM we "fixed" it by setting
the duration at 3 to 3.5hrs, even though actual duration was longer. This
way you get a more accurate calculation in the first 3 hours and you just
have to remember there's still about 10% IOB for the 4th hour though the
pump will read zero. This will be insignificant for small adjustments.
Also remember though the insulin kicks in after about 30 mins, you will not
see any impact on BGs for about 1 to 1.5 hours, hence why you test thrn
after a bolus. We go by the rule, meal boluses and small adjustment boluses
(under 1 unit)- test after 90 mins. Large adjustment bolus, test after an
Hope this helps.
Mum to Sarah, diabetic 10y years, pumping 4+ years
> Subject: [IPp] Re : I don't understand IOB
> Hi Morgan,
> I was looking back through the mail archives (having only just joined the
> POP group) and noticed your message. You've probably got your answers
> already by now, but ................ our understanding of it is that when
> you give the insulin bolus, it remains active in the body for a few hours
> (exactly how many hours varies between individuals, but our son was given
> a starting figure of 4 hours, using Novorapid). Novorapid (and I think
> Humalog also) are thought to peak after 2 hours, so this is when we do a
> post-meal blood glucose reading, after which the insulin activity
> gradually tails off. The problem with the pump feature when trying to
> correct for a high BG is that (with my son's pump anyway) it assumes the
> bolus amount will be used EVENLY over the 4 hours, so that if we wanted
> to correct after 3 hours it would say there is a quarter of the last
> bolus still active - in fact most of Owain's insulin takes effect in the
> first 2 hours, and very little would be left by the fourth, so we tend to
> override what the pump says and correct anyway! This usually works for
> him, but of course that's not to say it's right for everyone!
> Jackie (Mum to Owain, 7), UK
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