Around an hour before evening meal my readings are around 7..8 last insulin was over 6 hrs ago, how long before evening meal should I be taking my insulin, have tried between 15 and 30 mins but after eating usually drop to between 4.5 and 5.5 where I'm taking glucose tablets to stop it dropping further before evening meal is absorbed. cheers
Hello
@Charl,
I agree with
@rebrascora - trial and learning is now becoming essential for you.
There are at least 3 different main things going on here: the actual bolus insulin dose could be too great; the timing too long (as youqsuggest); and background activity from the day, or even carried over from a previous day. Before trying to investigate your bolus ratio or your pre- bolus timing, I'd like to ask a little more about your exercise and activity.
Since my surgery and the consequent declaration that I was insulin dependent, I have tried to return to a normal life and this has meant almost NOT having a fixed routine. Retirement allow me to pick and choose what I do on any one day. Very occasionally I might be very sedentary, usually I'm busy with mildly energetic jobs, more recently very energetic as we've packed and moved house and still busy with unpacking and reorganising; and just sometimes I'm relentlessly busy from early to late. At age 74 I tend to always stay in the range of aerobic exercise and activity, no longer willing to sprint for a bus or try for 4 (nor 8) minute mile runs!
But the amount of exercise and activity that I do can have a considerable difference on the behaviour of my BG and this is not easy to translate into a predictable formula - in the way that we convert carbs into potential glucose for insulin dosing. It's not helped my lack of variability of what I do daily, nor the carry over of activity response from a previous day. So you could have your insulin to carb ratios spot on for any one meal and your pre-bolus timing close enough but still get irregular BG responses. This needs awareness on your part of the principles and lots of trial and learning (rather than error!) in helping you judge what adjustments are needed to timings and insulin dosing.
Also, we all have a natural level of insulin resistance and I find my insulin resistance varies depending on the time of day and my level of BG at the time I take a bolus dose. So if I'm planning to eat my evening meal early, say 5.30pm the prebolus time needs to be a bit shorter than if I'm targeting dinner at 8pm; others can find this to be the other way round - hence trial and learning. Also, if my BG is highish as I prebolus, I not only need to include a correction component of bolus insulin but to allow longer for the prebolus to take effect - so 15 mins prebolus can become 30 or 40 mins; we can all be different - trial and learning. If its latish and I'm high I might add a greater correction and keep a more reasonable 15+ mins prebolus - letting the extra correction provide a substitute response, so that I'm not very delayed before I eat. All of these things are influenced by my need to consider others, since I don't live alone.
So with that background awareness I would be trying to establish if your day's activity has already set you up for reduced insulin resistance and therefore not needing much prebolus time or even needing as much insulin.
Once you get that response of dropping towards 4.5 and feeling you need to take some extra precautionary glucose I'd want to know if the extra carbs are causing you to end up higher than planned about 4 to 5 hrs later. If they are, then I would suspect that your basic insulin to carb ratio is too strong for that particular time of day as well as tweaking (shortening) the prebolus time. This is the challenge: we all respond a bit differently and we each have to explore and learn what is best for us.
A 4th thing that is extremely important is repetitiveness. If this occurs 3 days in a row, with roughly the same sort of daily activity and similar(ish) meals then it is more than reasonable to try to learn a lesson and make adjustments. But even with similar daily activity levels but quite different sorts of meals, it is really challenging to conclude much from that day's response.
A 5th thing is what sort of carbs are you taking when you are at at 4.5 and perhaps trending down? I would be eating a plain biscuit, or something fairly low GI and definitely not be taking dextrose, JBs or lucozade. For me this needs a "nudge" but not a big or fast response.
And a 6th thing would be to finger prick and confirm actual BG. When my CGM is showing low readings I need to verify that. Interstitial readings from CGM not only lag actual BG, but the algorithms (complex maths) built into the software get confused and become less reliable when near 4 or near 10. They can mislead on timings of responses. There are definite limitations to CGM data; however good and helpful the tech can be it IS NOT perfect. It would be prohibitively unaffordable and still would not be perfect for every indidual.
The good news, actually the very best news, is that just by virtue of your asking this question you are aware of responses and fluctuations and making your best efforts to deal with these fluctuations. From here on there is inevitably lots of refining techniques to learn
True hypo is actually 3.5mmol/L; we are told 4.0 rightly to build in some safety margin. Even at 3.5 such a hypo can be quite mild. I'm NOT encouraging you to work to such a fine margin, just suggesting that 4.5 trending down may not be as drastic as you think it might be. Your body's metabolic responses to carbs is actually a bit different at 3.5 than at 4.5. If you really are 3.5 or very close then your response needs to be "undiluted" high glucose, AND WAIT. If you take some dextrose then immediately start your meal you blunt the effect of that dextrose and your body is unable to speedily bring you away from 3.5 for possibly 2 hours and this plays havoc with your personal confidence as well as messing up your day or evening. But dextrose or similar at 4.5 followed quickly by other food is merely a mixed meal with a total carb intake, influenced by the high GI content which changes the metabolic processes, a bit.
The other really good news is that you are finding ways that YOU keep yourself SAFE. In my opinion, there is no perfect or ideal technique for D management and trying to get that perfection is relentless and very draining. I have increasingly accepted that provided I can keep my CGM daily graph more or less in range [4-10] then I'm not going to stress myself chasing a flat line at an average of anything! At my age I want to stay safe but not at any price. Whatever bits of damage that might occur because of BG issues they are now not so likely to cause problems as other age related problems - which can occur regardless of my diabetes. I worry for my 21yr old great niece, far more than for me.
