Blood sugar, or glucose, is the primary energy source for every cell in the body. While levels naturally fluctuate, a significant drop, known as hypoglycemia, means the body’s glucose supply is too low to meet its energy demands.
Understanding Low Blood Sugar
Hypoglycemia occurs when blood glucose falls below a healthy range. For individuals with diabetes, this is typically below 70 milligrams per deciliter (mg/dL); for those without diabetes, it’s generally below 55 mg/dL.
This reduction triggers symptoms as the body, especially the brain, struggles without sufficient fuel. Symptoms often start rapidly, including shakiness, sweating, and a faster heartbeat. Other indicators are dizziness, extreme hunger, irritability, and difficulty concentrating. If unaddressed, more severe symptoms like confusion, slurred speech, clumsiness, or loss of consciousness can occur.
Common Reasons for Drops
Several factors can cause blood sugar drops. For individuals managing diabetes, medication is a significant factor. Taking too much insulin or certain oral diabetes medications, like sulfonylureas, can lower blood sugar more than intended, especially if not balanced with food. Incorrect timing of medication or injecting insulin into muscle instead of fat can also contribute.
Dietary habits also impact levels. Skipping meals, delaying eating, or insufficient carbohydrates reduce available glucose. Meals high in refined carbohydrates can cause a rapid spike followed by an overproduction of insulin, leading to a sharp drop.
Physical activity is another frequent cause, especially for those on diabetes medications. Exercise uses glucose and increases insulin sensitivity, an effect that can last over 24 hours, potentially causing delayed drops.
Alcohol consumption can also contribute, particularly in excess or on an empty stomach, by hindering the liver’s ability to produce and release glucose. Illness or unexpected routine changes can also disrupt glucose regulation, leading to temporary drops.
Less Common Medical Conditions
Low blood sugar can also stem from less common medical conditions not directly related to diabetes.
Reactive hypoglycemia occurs when blood sugar drops within a few hours after eating, often due to excessive insulin release. Its exact cause isn’t always clear, but it’s sometimes linked to rapid sugar absorption after bariatric surgery or in individuals with prediabetes.
Non-diabetic fasting hypoglycemia occurs after prolonged periods without food in non-diabetic individuals. This can be caused by underlying conditions impairing glucose maintenance during fasting, such as severe illnesses, hormonal deficiencies, or rare tumors.
Hormonal deficiencies, like adrenal insufficiency (low cortisol) or severe hypothyroidism, can lead to hypoglycemia, as hormones like cortisol and growth hormone increase blood glucose. In children, insufficient growth hormone can also cause low blood sugar.
Rare tumors can also cause hypoglycemia. An insulinoma, a pancreatic tumor, produces excess insulin, leading to consistently low blood sugar. Non-islet cell tumors can cause hypoglycemia by producing insulin-like growth factor 2 (IGF-2), which mimics insulin. Severe illnesses, such as advanced liver disease, kidney disease, or sepsis, can also impair the body’s ability to produce or regulate glucose.
What to Do When Levels Drop
When experiencing low blood sugar symptoms, immediate action is important to raise glucose levels quickly. The “Rule of 15” is a widely recommended guideline: consume 15 grams of fast-acting carbohydrates, wait 15 minutes, then recheck your blood sugar. If it remains below 70 mg/dL, repeat the process until levels are above this threshold.
Examples of 15 grams of fast-acting carbohydrates include three to four glucose tablets, half a cup (four ounces) of fruit juice or regular soda (not diet), or one tablespoon of sugar, honey, or syrup. These are preferred because they are rapidly absorbed. Foods high in fat, like chocolate or peanut butter, are not ideal as fat slows sugar absorption.
Once blood sugar stabilizes above 70 mg/dL, consume a small snack or meal with protein and complex carbohydrates to prevent another drop. Keeping shelf-stable fast-acting carbohydrates readily available, such as in a car, at work, or by the bedside, can aid timely treatment.
When to Seek Professional Medical Advice
While many low blood sugar instances can be managed with self-treatment, certain situations warrant professional medical attention. Consult a healthcare provider if you experience frequent or severe episodes, especially if they occur often, are intense, or happen at night.
Medical help is also important if low blood sugar occurs without an obvious reason, not linked to medication, diet, or exercise, as unexplained drops could indicate an underlying medical condition. If symptoms do not respond to self-treatment using the “Rule of 15” or worsen, seek medical consultation.
In severe cases, such as loss of consciousness, seizures, or inability to swallow or respond, emergency medical care is necessary. Do not attempt to give food or liquids to an unresponsive person due to choking risk. Emergency glucagon, if available, can help. Always consult a doctor before changing medication regimens, particularly for diabetes, to prevent future hypoglycemia episodes.