A sharp or sudden rise in your blood sugar level, typically followed by a decline or crash, is called a glucose spike. The fluctuations in your blood sugar levels are normal and happen multiple times during the day, but a true spike is different. 

Glucose spikes or blood sugar spikes can occur for various reasons, like consuming a high-carb diet, lack of sleep, dehydration, stress, intense exercise, or certain medications. Research states that very low or high blood glucose levels can disrupt cellular functions.
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