Insulin dosage, carb ratio changes

I use insulin sensitivity and carb ratio’s to estimate my novolog dose before each of 3 meals; the estimate includes a correction for deviations from the target level, and an amount to compensate for grams of carbohydrate.
I use 1 lantus dose per day to attempt to prevent major rises or drops of blood glucose levels overnight.
Both the insulin sensitivity and carbohydrate ratio vary a lot. They’re much higher in warmer weather. They’re lower in the morning. Does anyone know of some good science reporting on this?


We can really all vary how we respond to heat,

But here is a small informal study of hot showers and blood sugar levels.

My blood sugar rockets sky high if I take a hot shower in the morning,by night time it still goes up but not as much. But I know people who purposely take a hot shower to lower their BG levels. Because of either DP or right now it’s FOTF. I need a lot more insulin in the morning even when I don’t eat.


Thanks for the lead! I commented on their study and hope to join in their work.
The hot shower effect varies from person to person, apparently, but its direction is consistent on a personal basis. Maybe a similar result would emerge for insulin sensitivity with regard to ambient temperatures and/or seasonality.

I am on an insulin pump (10 years plus) so my experience may be irrelevant. After adjusting my insulin resistance and carb ratio during the first six months, I have not changed the ratios over the succeeding years except lowering the resistance time once when I switched to Fiasp from NovoLog.

Thanks for the data point! If I were using a pump, I would be interested in the background rate of insulin usage. I’ve never used a pump, but I understand that some of them will automatically adjust the background infusion rate, so as to avoid overnight lows, etc. In my case, I try to set the Lantus dose just right, to avoid lows but not go too high.

I recently spent 12 days in the hospital and was not allowed to use my pump. Instead, I had to follow the hospital’s protocol of Lantus and humalog injections. One night I had to consume almost a quart of orange juice just to bring my BGs over 70 and another night my meter read over 400.