Hi @Timostags,From my experience on insulin for 52 years and not as professional advice or opinion:
I assume you are on MDI (multiple daily injections, with basal/bolus regime) or an insulin pump.
My sensitivity to insulin varies between morning and night, increases in the hours after exercise and possibly for up to 24 hours after.
Stress and excitement decrease my insulin sensitivity and to a lesser extent my insulin sensitivity varies with season and weather.
Last night I was watching early series of the TV series Spooks and, as is my usual practice, I increased my pump's basal by 20% for 4 hours to offset the effect of adrenaline on my insulin's effectiveness and thus BSLs.
With doing my hobby of making kites, the concentration required for a difficult technique or design can send my BSLs up whereas flying the completed kite on the beach relaxes me and my insulin sensitivity is enhanced.
On my pump I alter my insulin sensitivity factor from a weekday programme to a kite flying programme to allow for the relaxation and exercise involved in the latter. Say from 1unit:1.3 mmol/l to 1:1.5mmol/l but that is an individual figure.
Lastly the onset of a viral infection, dental troubles or having a vaccination upsets the insulin sensitivity apple cart.
Then there are other instances where the cause of a BSL upset is related not to insulin sensitivity per se but to things like, injection of insulin into a frequently used site leading to variable absorption, a bent cannula of a pump's needle port under the skin leading to restriction of insulin delivery, the rare case of accidental injection of insulin into a blood vessel or muscle (leading to quicker uptake and hypos) or where insulin may have been degraded by freezing or being overheated.
If I have reliable CGM running (and could afford it) I at least would have the opportunity to see what the response to any adjustment to my insulin sensitivity factor is, without resorting to frequent finger pricks!! Also there is the accompanying question about whether my insulin to carb ratio is appropriate and knowing that that ratio also varies with the time of day etc.
In short all I can do is try to work out what regime of insulin vs BSL and insulin vs carbs works for me at a particular time of day, season, activity and for sick days etc. and be vigilant for other factors such as insulin absorption etc.
I know that you may have hoped for a straight forward answer and certainly an insulin pump with CGM and closed or semi-closed loop is likely the current gold standard but we have the challenge of trying to emulate the human body's sophistication in blood sugar control developed over thousands of years. I would like to hear of what others say, too.
