BGs before exercise

I spend 20 minutes on my exercise bike most afternoons in an attempt to keep myself reasonably fit. I usually reduce my lunchtime QA so that my BG before this is around 10 or 11. Would it be better to inject the correct QA and then take extra Carbs if necessary before the exercise? Or doesn't it matter?

Hi alan. Whatever the rulebook says I would agree with your current regime as personally I feel that the alternative option of taking the correct QA and then taking on additional carbs to make up BG levels in some way defeats some of the benefits of doing the exercise. Andy

Hi Alan

As every diabetic is different I think that only you after experimenting can find a 'happy' situation with your BG's. I do agree with what Andrew has said and from experience using the 'rulebook' etc I found that eating extra CP's before exercise/reducing insulin before exercise just resulted in very high BG's after as there was not enough insulin left in my body!
I have found that matching CP's with the QA is good (but I do have jelly babies with me), I do reduce my BI on an exercise day and find that I can eat 1 CP before bed without having to take any QA.

Good luck

Thanks very much for the responses - very re-assuring.

Alan, just my 2p, trial and error is needed as we're all different.

For me it would depend on exercise intensity, if I knew I was doing an aerobic pootle / fat burner ride I wouldn't do much different with insulin unless it was going to be over an hour when I would lower QA, over 4 hours I would lower background and take sugar just in case (at lower intensity, very rarely needed).

For intense anaerobic sessions I wouldn't lower QA as I find cortisol and liver/ muscle glycogen spike my BG so having that QA on board is good.

This all works fine in theory until you go out and do a new route and find it has more hills than you expected or there is a massive headwind! On long rides for this reason I will take NovoRapid pen with me too as I feel lousy if BG spike is too much.

Hope this helps a bit? Trial and error though? Regardless if I go out on my bike I have pockets full of energy gels just in case

Phil

Wow, Phil - I'm not anywhere near your league! I limit myself to 20 minute sessions, but I do get out of breath and get the old heart pumping.

I'm probably 50 years older than you - so that's my excuse and I'm sticking to it!
Have you done any racing? Cycling is a great sport, you should try it.

How soon after lunch are you exercising Alan? If it is within a couple of hours, then your current regime is probably fine. If it is 4 hours or so, then perhaps take lunch a bit earlier, or exercise a bit later and take the correct insulin, or one unit less than what you would take if you weren't doing the exercise.

How far do your BGs drop during the 20 minutes of exercise?

Hello Warwick, I usually exercise about two and a half hours after lunch.

My BGs go down by 5 or 6, so if I'm about 11 before I start I usually have some jelly-babies and a cereal bar afterwards to keep my BG from going down too far as my body recovers - that's about 2 or 3 CPs.

Hmmm, options as I see it are:

1) Keep the status quo.
2) Increase the time period between lunch and exercise so there is less QA around.
3) Eat some quick-acting carbs just before the exercise.
4) Have a low-carb lunch so that you don't need much QA which may assist the BGs to stay steady during the exercise.

Thanks Warwick. I think I'll keep things as they are for the time being, but there are a lot of useful tips here - thanks everyone.