Hypoglycemia · What Is It, Causes, Testing, Treatment, and More

Signs and symptoms of hypoglycemia include hunger, fatigue, shaking, sweating, pale skin, headache, and dizziness. If hypoglycemia persists, these signs and symptoms may worsen, resulting in confusion, slurred speech, blurred vision, fainting, seizures, or even coma.   

Most individuals don’t develop symptoms of hypoglycemia until their blood glucose level falls below 55 mg/dL. However, some people may become symptomatic when their blood glucose falls below 70 mg/dL; while others, like those with long-standing diabetes, may experience impaired hypoglycemia awareness and experience symptoms only when their glucose falls severely low, which puts them at higher risk for life-threatening consequences. Additional factors associated with decreased hypoglycemia awareness include older age, recurrent episodes of hypoglycemia, and taking certain medications, such as beta-blockers, which can mask adrenergic symptoms like tachycardia and tremors, making it harder to recognize hypoglycemia. 

Individuals who have diabetes and take insulin or other diabetes medications should be aware of symptoms of hypoglycemia and check their blood sugar with a blood glucose meter if they feel unwell. Blood sugar levels below 70 mg/dL confirm hypoglycemia, and levels below 54 mg/dL may call for immediate action to raise blood sugar levels. 

Individuals with recurrent episodes of hypoglycemia or inadequate glycemic control, may benefit from a continuous glucose monitor (CGM), a sensor-based device that tracks blood glucose levels in real-time. CGMs have a tiny sensor inserted under the skin, usually in the upper arm or abdomen, which measures interstitial glucose levels. This signal is sent to a transmitter attached to the sensor, which sends glucose readings wirelessly to a receiver, smartphone, or smartwatch every 1-5 minutes. Most CGMs can be configurated to provide alerts for high or low blood sugar, helping prevent hyperglycemia or hypoglycemia. 

To treat hypoglycemia, blood sugar levels must be raised back to healthy values. To do this, people are typically asked to eat or drink 15 grams of fast-acting carbohydrates—for instance, glucose tablets, a fruit juice box, or one tablespoon of sugar or honey are common remedies. As these sugary foods and drinks don’t have any proteins or fats, they are more easily processed in the body. Blood sugar levels should then be rechecked 15 minutes after consuming at least 15 grams of carbohydrates. 

If, after 15 minutes have elapsed, blood sugar levels are still below 70 mg/dL, the individual should eat or drink 15 more grams of fast-acting carbohydrates and recheck their blood sugar levels after another 15 minutes. This is generally referred to as the 15-15 rule and is repeated until blood sugar levels are above 70 mg/dL. Once recovered and no longer in a hypoglycemic state, people typically benefit from eating a more substantial snack or meal containing complex carbohydrates (e.g., whole grains, legumes, vegetables, nuts, etc.) which provide sustained energy.  

Of note, hypoglycemia induced by sulfonylureas (e.g., glibenclamide, glipizide, gliclazide) can last for hours or even days, especially with long-acting agents like glibenclamide. That’s because sulfonylureas stimulate insulin secretion regardless of blood glucose levels, leading to persistent hypoglycemia. Even after initial treatment, sulfonylurea-induced hypoglycemia can recur, requiring prolonged monitoring and repeated glucose administration over time. 

Individuals suffering from severe hypoglycemia may need medical assistance to recover. If someone is unconscious and cannot eat, they may require a glucagon injection or intravenous (IV) glucose. Generally, individuals with diabetes prone to hypoglycemia will have a glucagon kit for emergencies. However, if there is no kit available, those helping should call 911.  

A variety of measures can be taken to prevent hypoglycemia from occurring. Individuals who have diabetes or are struggling with reactive hypoglycemia should try to include more complex carbohydrates in their diet. Examples of complex carbohydrates include whole grains, beans, and vegetables such as broccoli. Unlike simple carbohydrates, such as honey, sugar, and fruits, complex carbohydrates take longer for the body to break down, which helps maintain blood glucose levels constant over a longer period of time.  

If hypoglycemia frequently recurs in an individual with diabetes, their clinician may suggest changing, stopping, or adjusting their dosage of insulin or other diabetes medications.  

In individuals without diabetes, treatment of underlying conditions may be necessary to resolve the associated hypoglycemia.