Hi, can you help? Ive had Diabetes Type 1 for 43 years, currently on a Medtronic 640g pump with a Guardian sensor. Usually my levels are pretty well balanced, but for some reason over the last week, Im waking up at 3am to a very high level, then Im giving a correction dose to get it down. By the time I wake up in the morning at about 7.30am, Im having a hypo. Does that mean the sensitivity ratio is too high or the basal levels arent quite right at 7.30am? Or a bit of both, Id welcome some advice, thanks.
Hi @Scrumpyjack65 Sally. Are you correcting based on the guardian reading? If no, what’s your finger bs reading? Either way, 3am is a time I need highest basal, but it doesn’t last until morning. What happens to your blood sugar if you don’t correct I am guessing it would drop some anyway. Also when is your last bolus and what are you eating for dinner?
When the weather warms up I need to adjust basal a bit.
Im guessing it’s probably a basal adjustment. If your corrections work otherwise I wouldn’t start there. Use the CGM to track blood sugar but g2 and g3 should be verified by finger stick every couple hours when checking basal rates. Cheers good luck 
Hi @joe, thanks for coming back to me. Im correcting on the BG and guardian rating as they are pretty much the same at the 3am wake up time. If I dont give a corrective dose then Im way high, like 22 in the morning, Last bolus is usually about 7.30pm but its only for covering about 30g carbs. I think you’re right on the basal settings. I’ll give it a go tonight, thanks 
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You’re welcome @Scrumpyjack65. Go easy on the change though. It shouldn’t, in my opinion, be more than that correction (that made you low) over 4 hours. All the best!
Hi Sally @Scrumpyjack65, my thinking is close to what @Joe wrote, and my “guess”, based on personal experience, is that your glucose level MAY be corrected by your basal rates without needing a bolus. If you do bolus, modify [reduce] the dose similar to the way the “automatic” correction bolus is calculated in the Control IQ. That is, only 60% of the calculated bolus is delivered.
What you may need to be doing, is reevaluating your basal rates. This is done by watching how closely your basal alone, without correction of either food or bolus, holds your glucose close to your desired target; do this observation over at least a 12 hour period. With my pump and CGM, I’m able to observe this interaction using software, such as the JDRF sponsored Tidepool "Daily Report. On one page, this report displays a line-graph of CGM readings, and right below the CGM line, is a bar-graph of basal delivery; the graph also shows food carbohydrates entered in the pump and bolus delivered.
Your “sensitivity factor” set in the pump is important too; keep in mind that your insulin sensitivity cam most likely differ over the time of day. If you are considering using one of the AIDs [Automatic Insulin Delivery systems], it is very important that sensitivity, basal, and bolus rates/ratios be set to your body’s current needs - yes, those “needs” change.