Hello
@Simon v (good name
)
It would probably be worth starting a new thread, but with that said I'd have missed the comments in the previous posts had you not posted here.
To kick things off, here are some thoughts - I'm a cyclist though not a runner.
To answer your question about pump suspension (I'm on MDI fwiw, so this is my understanding), if the pump is using Novorapid, there will still be the remnants of the previous doses in whomever's system for 3-5h, so there is still some background insulin. Quite what happens when the race gets beyond that ~5h I don't know - at that point there is probably a danger of DKA. While the muscles will absorb glucose in the absence of insulin when exercising, I don't know how much/whether any background insulin would also be required. Certainly as soon as the race stops it would cause problems.
For you doing MDI, I'd be very tempted to split your basal dose in two (though it depends what your basal insulin is - if it has a duration of ~24h this is viable, for longer acting insulins it won't be very/at all effective), Assuming you have the right insulin (Lantus/Abasaglar for example) then you can slightly reduce the evening dose (if you want, or leave it alone) and drastically reduce the morning one (e.g. to 1/4 or 1/2 of usual, or even skip it completely - your previous evening basal will still provide coverage during the day even if you skip the morning dose).
I moved to a split (for long-ish distance cycling) to avoid running high overnight due to insufficient basal coverage (and to avoid running low overnight after exercise), and to still be able to have some basal insulin on-board during the day when I'm riding. The evening after exercise I take either a slightly reduced or normal evening basal dose depending on how long/hard the ride was (and if I'm riding again the next day) and whether I feel like I'm likely to run low overnight.
Re your breakfast, as long as you have basal insulin on-board, once you start exercising that insulin will become very effective (your muscles become very sensitive to it) so the glucose from breakfast will be used. The difficultly I find is that there is a delay in this heightened sensitivity occurring, and in addition my liver chucks out glucose to "help me" for the first ~1.5h. I need to take some bolus to balance these out, but not so much that I then go hypo once muscle sensitivity kicks in.
