Cartoon by the fabulously talented Haidee Soule Merritt

This is a precautionary tale. Don’t forget, as I did, that the summer heat and humidity can affect your skin, your body temp, your insulin viability, your sanity. For some summer pointers, click here, “How to deal with heat and diabetes.”

For the past two days my blood sugar has been higher than usual. Yesterday, when it went up to 180 mg/dL around 10 am, after waking at 105 mg/dL, and not having anything to eat, only a cup of coffee with cream, I froze. What the f#@k! Granted, my blood sugar rises 20-30 points regardless of no food when I wake from the Dawn Effect, but 75 points was just not right.

My mind began the tedious backtracking. Was my mealtime Humalog bad? Hmmm..maybe, it looks a little cloudy. Was my long-acting Tresiba bad? Maybe, I couldn’t remember when I started it. Were either, or both, spoiled from my hot apartment? Granted the air conditioner is on by the afternoon, but not in the morning or overnight. How hot was it anyway in the kitchen where I keep my Tresiba in a cup on the counter? The Humalog I keep in the fridge.

Quickly I asked the husband if we had a thermometer and if so to bring it into the kitchen. Of course he did. The temperature was 26 degrees. Well, what do you expect when you live with a Dutchman? 26 Celsius. Now I had to go look that up. That’s 77F. Then I had to look up the threshold for temperature and 86F is the magic number, 30 degrees Celcius, before insulin presumably goes bad.

Frankly, I had no idea what caused the rise in my blood sugar that lasted just about til 6 PM, regardless of the fact that I kept taking half units of my mealtime insulin to nudge the number down. It barely budged. Until of course it came crashing down to 70 mg/dL mid-afternoon with my Dexcom arrow pointing downward still. I swallowed three glucose tablets. My blood sugar raced up to 132 mg/dL and then seemed to leave me at 122 mg/dL and stay relatively steady for the rest of the night.

Still, I stayed up past midnight just to make sure my scariest theory – that I had no Tresiba onboard – was untrue and I wouldn’t find my blood sugar climbing to a DKA number. It didn’t.

This morning I woke up with two revelations. The one on my Dexcom was a happy 82 mg/dL. The other was given the heat wave, I haven’t done my daily hour exercise walk for the past several days. I know this daily exercise keeps me more insulin sensitive. So, was that the reason all along? Maybe my insulins are fine, my body is not dehydrated, I just wasn’t insulin-sensitive with the lack of exercise?

I can’t know for sure, but for now I’m going with this theory. While I’m writing this I’m at a pleasant 106 mg/dL so I’m inclined to think it’s a good hypothesis.

All to say, don’t forget the summer heat can play havoc with you and your insulin. This was in my inbox this morning from Hedia, a Danish diabetes app. With its oddly appropriate timing, I thought I’d share – “How to deal with heat and diabetes.”