A spike means glucose is elevated
Hyperglycemia means high blood glucose. In diabetes it can result from too little insulin, reduced insulin effectiveness, food, illness, stress or other factors. High glucose can occur without dramatic symptoms, especially when the rise is gradual.
A true crash means glucose is low
NIDDK describes hypoglycemia as low blood glucose that can cause shakiness, hunger, tiredness, dizziness, confusion, irritability, headache and other symptoms. Severe hypoglycemia can cause loss of consciousness or seizures and needs urgent treatment.
Feeling tired is not enough to label either one
Sleep loss, dehydration, a large meal, stress, medications and many medical conditions can produce fatigue or lightheadedness. If you need to know whether glucose is high or low, objective measurement and clinical context matter.
| Pattern | Typical question to ask |
|---|---|
| Possible high glucose | Is the measured glucose actually above my clinician-set range, and is this recurring? |
| Possible low glucose | Is the measured glucose low, and do I have a plan from my care team for treating it? |
| Symptoms without a measurement | What other causes could explain this, and do I need medical evaluation? |
Sources & verification
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