Elsewhere at Type1News you’ll find information about how blood glucose control can change over the course of a single day. One of the final pieces of the puzzle has to do with changes over a much longer timespan – over the course of a year.
In Spring a young man’s fancy lightly turns… Tennyson observed, and most of us observe a change in our metabolism as the days grow longer. Given that insulin requirements are closely tied to metabolism, there is bound to be a need for adjustment as the seasons change. They just may not be as you expect. Please read this particular article with caution, as your results, as they say, may vary.
The person in our household with Type 1 diabetes is still in his 20’s, and so these seasonal effects are still fairly pronounced. I think most of us are aware that heavy exercise can make one’s cells capable of burning some carbs in an absence of insulin. Because of this, one might think that less insulin is needed in the spring. We’ve actually found the opposite.
It seems that digestion is affected by these metabolic changes more than the body’s ability to burn carbs. So, in the spring, we’ve found that more insulin is necessary – and faster – after meals. In our case, this adjustment is made by altering the calculated carb-to-insulin ratio. Each season, spring and fall, we spend a few days nudging this ratio until we’re again getting good blood sugar control. The change comes on pretty quickly in the spring, over maybe 10 days and then there’s no further progression. In the fall it seems to take just a little longer, but it is remarkable how quickly the metabolism slows back down for winter.
Any change in the insulin ratio can be more complex to implement than you think. A change in ratio from daypart-to-daypart is a prescribed by our endocrinologist as a preferred method of pump managment. Some of these changes are probably legitimate differences in daily metabolism, but some of these adjustments seem to be to “trick” the pump or alter the curves for best result. Overlay an overall ratio change to this system, and the results can be unpredictable. Approach these seasons with caution!
In addition to the normal circadian effects, be on the lookout for seasonal allergies. Inflammation caused by allergies raises blood glucose, sometimes fairly dramatically, resulting in some of those surprise mornings near 300 that we hate to see! Antihistamines may not only address allergies you experience, but they may also suppress a general background inflammation you were unaware of, resulting in dangerous lows. We try to make extra time for mid-night glucose checks and calibration in these tricky times of year.
If you go into your first year of diabetes management expecting these effects, you’ll stay safer and learn more that first year, so the subsequent years can be more familiar. As always, good luck. Our thoughts are with you.
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