I have a question before my health check-up.

I work for a company that requires annual health checkups. Since it's mandatory, I tend to manage my health well. If my results are high, I need to undergo a re-examination. That also means taking time off to go, so I feel a bit self-conscious.

Everything else is fine, but my blood sugar levels have been high lately. I am in good physical condition, but I really enjoy sweet foods.

Still, I am regularly monitoring my levels while donating blood. They are still within the normal range. I heard that I should observe something called HbA1c rather than blood sugar levels. Why is that?