When to Check Your Blood Sugar

How often you need to check depends mainly on your treatment. Someone on insulin needs more information than someone managing with diet and metformin.

The useful principle is to test with a question in mind. A random reading in the middle of the afternoon rarely teaches you anything. A pair of readings — one just before a meal and one two hours after it — tells you what that particular meal did to your blood sugar. That is something you can act on.

So rather than testing at the same time every day out of habit, rotate. Check around breakfast for a few days, then lunch, then dinner. You will build a picture of which meals are giving you trouble, which is far more useful than a long list of fasting numbers.

Check more often when something changes: a new medicine, an illness, a change in your routine, or a stretch of unusual activity. Also check if you feel unwell in a way that could be low blood sugar.

Your doctor can tell you what frequency fits your treatment. If daily testing is making you anxious rather than informed, say so — that is a reason to change the plan.