Blood glucose is commonly considered too high if it is higher than 130 mg/dl before a meal or higher than 180 mg/dl two hours after the first bite of a meal. However, most of the signs and symptoms of high blood glucose don't appear until the blood glucose level is higher than 250 mg/dl.
Subsequently, one may also ask, what causes high levels of glucose in the blood?
High Blood Sugar Causes. Diabetes mellitus is one of several persistent conditions causing high blood sugar levels. When food, exercise, and insulin are not balanced, blood sugar levels rise. Stress: Emotions can play a role in causing hyperglycemia, but should not be used as an excuse for poor control of diabetes.
How do you feel when your blood sugar is too high?
Your blood sugar may be too high if you are very thirsty and tired, have blurry vision, are losing weight fast, and have to go to the bathroom often. Very high blood sugar may make you feel sick to your stomach, faint, or throw up. It can cause you to lose too much fluid from your body.