You can't always prevent hypoglycemia, or low blood sugar, and some people may not feel it when it happens. But by monitoring your blood sugar and knowing the symptoms, you can treat it before it gets dangerous.
Sweating, hunger, pale skin, and trouble focusing are other symptoms. If your blood sugar is low or you can't check it, take some quick-acting sugar like juice, a tablespoon of honey, or 4 teaspoons of sugar. Wait 15 minutes, check again, and repeat until you feel normal.