Going from 120 to 250 in an hour. Could it be the heat?

Yesterday and today, my BG rose very rapidly over about an hour. Yesterday woke up at 86 (8:00) and hit 265 at 10:30. Today my 8:00 reading was 120. I watched it rise until my CGM read over 200 at 9:00. It switched out my pump stuff. Tested at 255 and corrected. (It’s not DP, as I have basal settings for that and have had no problems like this until yesterday. Insulin was from a new bottle and everything was changed Sunday.) BGs were fine the rest of the day yesterday.

It is really hot here right now, like over 100. I’m in the air conditioning. Have to go out around 11:00.

No idea what’s going on, but going up that high that quickly makes me feel awful


I dunno. I think you need more data. But, as a Minnesotan (we are all naturally preoccupied with the weather), I do definitely believe it plays a role. I spoke about this with another friend with chronic illness the other day because with the summer heat, we both felt like our medications were more ‘active.’ Sometimes heat can speed up circulation and make insulin more effective. But, dehydration could play a role in bumping BG’s up. Diabetes black magic - its so hard to say. I find the effect of the cold more obvious.

The place where I live has very high swings in temperature, similar to parts of Russia, because we are landlocked far from the ocean. So, we are all sorta preoccupied with the influence of the weather.


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I usually find that heat increases my insulin activity and decreases my blood sugar, so for me anyway that would not be my attribution. If I’m out in the heat all day, it’s remarkable how much my insulin needs can drop. YDMV though!


What sort of data?

I think you need to have more days of it happening before you can decide if it’s a continuous problem since you’re okay in the afternoon.

But every morning, anywhere from 6am to 9am my BG shoots up, not eating anything, nor drinking anything, mostly still being in bed. It is not uncommon for me to go up 100-200 points within an hour to 2 hours. My arrow on my sensor usually points straight up or angling up. If I drop in the middle of the night it starts to happen even sooner.

I have a lot higher basal setting starting at 6am, and then even more at 9am, but I can’t compensate enough in a presetting for that climb not knowing exactly when it’s going to happen. So I have to catch it when it starts for an extra dose. Hopefully sooner versus later,

When it first started I don’t believe it happened every day. But I didn’t even know that it was happening every day until I got my CGM. My thoughts had always been , gees I’m high today I wonder why, to I’m normal but not knowing within 2 hours I wasn’t going to be normal and maybe wondering at an afternoon bloodstick why I was so high. sometimes I did catch the rise and wondered what had happened that it shot up.

Going up quickly sometimes makes me not feel well either, I’ve learned never to eat in that time period or to take a shower then as both help raise my BG and I can feel really bad. I delay eating in the morning and I take my shower in the evening when it doesn’t seem to make my BG go up as much.

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Dehydration makes my BG’s go crazy high but since it’s happening in the morning I wouldn’t attribute it to that either. What did you eat the last 2 nights? Did you eat anything late at night? Did you do anything unusual? These are just the basic questions I’d ask myself if I was having wonky BG’s that we sometimes forget to ask ourselves.

I would try drinking a big glass of water before bed and maybe even something to replenish electrolytes like broth and see if that helps.

We always eat at 6pm.
Sunday night was some leftovers. Bedtime BG was 176. I corrected, did well overnight. Underdosed for food, I think.
Monday was a BLT built on one slice of bread. 116 at dinner. 99 at bedtime. One low last night, corrected with juice. 120 at fasting BG.

Hydration is not a problem. I drink iced green tea and water all day.

For me going from 120 to 250 in an hour (and back again the next hour) with no discernible cause whatsoever in terms of caloric input, insulin dose, or exercise is a sign that I’m still alive.


Yea, my basals might not work as effectively sometimes. If you really feel bad and have trouble recovering, could you shoot some temp basal increase tomorrow so that you aren’t committing to a permanent basal change and just see what happens? Something moderate enough so you don’t go deadly low if that pattern disappears, but still takes the edge off that high. Split the difference, maybe? I would watch it for a week before implementing a permanent change in basals, but I’m cautious about basal changes.

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