I was told to assume a flat profile over 4 hours - a quarter of the insulin is used each hour.
So, if I took 8 units at midday, I would have
- 6 unit of IOB at 1pm
- 4 units at 2pm
- 2 units at 3pm
- none at 4pm
Why are you asking?
What calculations are you making that needs to know iob?