What are the first warning signs of high blood sugar?

Early high blood sugar symptoms can include increased thirst, frequent urination, fatigue, headache and blurred vision. Symptoms usually develop gradually and may not become noticeable until glucose is significantly elevated.(( Mayo Clinic — Hyperglycemia in Diabetes: Symptoms and Causes Mayo Clinic — Hyperglycemia in Diabetes ))

What are the symptoms of low blood sugar?

Common low blood sugar symptoms include shakiness, sweating, hunger, dizziness, irritability, weakness, rapid heartbeat and confusion. Blood glucose below 70 mg/dL is considered hypoglycemia.(( ADA — Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026 ADA 2026 Standards — Section 6 ))

How can you tell the difference between high and low blood sugar symptoms?

Increased thirst and frequent urination are more characteristic of high blood sugar , while shakiness, sweating and sudden hunger are more typical of low blood sugar . Because symptoms can overlap, checking your glucose is the most reliable way to determine whether your blood sugar is high or low.

Can you have high or low blood sugar without symptoms?

Yes. Some people have high blood sugar without noticeable symptoms. People who experience frequent hypoglycemia can also develop impaired hypoglycemia awareness , which reduces or eliminates typical warning symptoms of low blood sugar.(( ADA — Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026 ADA 2026 Standards — Section 6 ))

What should you do if your blood sugar is below 70 mg/dL?

If you are conscious and able to swallow safely, consume fast-acting glucose or another carbohydrate containing glucose and check your blood sugar again after 15 minutes. About 15 grams of carbohydrate is commonly used , although individual treatment recommendations can vary.(( ADA — Glycemic Goals, Hypoglycemia, and Hyperglycemic Crises: Standards of Care in Diabetes—2026 ADA 2026 Standards — Section 6 ))