When you are stressed, your body releases stress hormones that prompt the liver to release glucose for a quick energy supply. In people without diabetes this is balanced out, but in diabetes it can cause noticeably higher readings.
This is one reason blood sugar often rises during illness, infection, surgery, injury, poor sleep, or periods of intense emotional strain. It can be confusing when your diet and medication have not changed, but the readings climb anyway.
Managing stress through sleep, physical activity, relaxation techniques, and support can help overall control. If your readings stay unexpectedly high during illness, or you cannot keep fluids down, contact your care team, as sick-day management sometimes needs adjustment. Do not change insulin or medication doses on your own without advice.