Sign out
Keeping your blood sugar within a healthy range is the best way to manage diabetes. Know what symptoms to watch for that tell you if your blood sugar is too low or too high.
It’s important to understand the causes behind those symptoms. This will help you avoid extremes by fine-tuning your and planning for changes in your daily routine (such as travel or catching a cold) that will affect your levels.
Very low blood sugar
Blood sugar below 70 mg/dl is low blood sugar, or hypoglycemia. However, you will most likely notice symptoms before you can confirm your low blood sugar level through testing.
Symptoms
- Weakness or fatigue
- Dizziness
- Headaches
- Blurry vision
- Sweatiness
- Fast heartbeat
- Anxiety
- Hunger
- Irritability
- Shakiness
Onset
Symptoms are often sudden.
Causes
- Being more active than usual
- Side effects from other medications
- Alcohol, especially on an empty stomach
- Missing or delaying a meal or snack
- Too much insulin or diabetes pills
Effects
If low blood sugar is left untreated, you may pass out.
How to treat seriously low blood sugar
Check your blood sugar. If it’s below 70, follow the 15/15 rule to avoid serious problems:
Consume 15 grams of carbohydrates, such as 3 to 4 fast-acting glucose tablets or 1⁄2 cup of juice. Always choose liquid sources of sugar before solid foods, if you can. Liquids raise your blood sugar faster.
Wait 15 minutes.
Check your blood sugar again. If it’s still below 70, repeat these 3 steps.
Once your blood sugar gets back above 70, eat a healthy snack to continue settling everything back to normal.
Very high blood sugar
Blood sugar above 240 mg/dl is high blood sugar, or hyperglycemia. When blood sugar is this high, it’s serious and needs to be lowered right away.
Symptoms
- Drowsiness
- Blurry vision
- Extreme thirst
- Hunger
- Frequent urination
- Dry skin
- Slow-healing wounds
Onset
Symptoms often start slowly. Some signs (e.g., blurry vision or slow healing) may take longer to notice than others (e.g., increased thirst or hunger).
Causes
- Too much food
- Too little insulin or diabetes medication
- Illness
- Inactivity
- Stress
Effects
If high blood sugar is left untreated, it may lead to a medical emergency.
How to treat seriously high blood sugar:
- Check your blood sugar every 4 hours.
- Drink 1 to 2 cups of water, caffeine-free or calorie-free liquid, diet gelatin, or clear broth.
- If your blood sugar remains above 300 mg/dl for 8 hours, call your doctor.
Bottom Line
Blood sugar below 70 mg/dl is too low. Blood sugar above 240 mg/dl is too high. Treat both conditions immediately.
Call your health care team if your numbers don’t improve.