Hypoglycemia, popularly known as a sugar drop, is one of the most common medical situations in people with diabetes, although it can also affect those who do not have it. Understanding what it is, how to recognize it, and how to act can make a huge difference, especially in the most severe episodes.
In this article, you will find all the information you need: from the medical definition to the types of hypoglycemia, its most common symptoms, the causes that trigger it, and the most effective treatment to recover quickly.
What is hypoglycemia?
Hypoglycemia is a condition in which blood glucose levels fall below what is considered normal. Glucose is the body's main fuel, and when it is scarce, the body and brain cannot function normally.
From a clinical point of view, it is considered hypoglycemia when blood glucose falls below 70 mg/dL in people with diabetes. In people without diabetes, the threshold may be around 50-55 mg/dL, although symptoms can appear earlier if the drop is very sudden.
It is important to know that hypoglycemia is not a disease itself, but a warning sign that can have multiple causes. That is why knowing it well is key to acting in time.
When is it considered hypoglycemia?
Although 70 mg/dL is the most commonly used reference threshold in clinical practice, values can vary depending on the person and context. In people with type 1 diabetes, frequent hypoglycemia episodes can cause the body to stop perceiving the usual symptoms, which is known as asymptomatic hypoglycemia or hypoglycemia unawareness.
The classification by severity levels is as follows:
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Mild hypoglycemia: glucose between 54 and 70 mg/dL. The person is conscious and can self-treat.
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Moderate hypoglycemia: glucose below 54 mg/dL. More intense symptoms appear and reaction ability may be impaired.
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Severe hypoglycemia: the person cannot take care of themselves. They require external help or urgent medical intervention.
Symptoms of hypoglycemia: how to know if your blood sugar is low
Symptoms of a sugar drop can vary quite a bit from one person to another and depend on how quickly glucose falls, not just the final value. This explains why some people experience intense symptoms with relatively normal glucose levels while others notice nothing even with very low values.
Adrenergic symptoms (the body activates the alarm system):
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Tremors or shivering sensation
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Palpitations and rapid heartbeat
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Sudden cold sweating
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Paleness
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Intense hunger sensation
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Anxiety or nervousness without apparent cause
Neuroglycopenic symptoms (the brain starts receiving less glucose):
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Difficulty concentrating or thinking clearly
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Headache
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Blurred or double vision
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Confusion or disorientation
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Slurred speech or difficulty speaking
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Extreme drowsiness
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In severe cases: seizures or loss of consciousness
How to know if my blood sugar is low without a glucometer?
The most reliable way to confirm hypoglycemia is to measure glucose with a glucometer or continuous glucose monitor (CGM). However, if you don’t have one handy, there are physical signs that can guide you:
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Sudden onset of trembling, cold sweat, or urgent hunger, especially if you haven’t eaten for hours or have done intense exercise.
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Feeling dizzy or "empty-headed" combined with irritability.
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If you take insulin or diabetes medication and have gone longer than usual without eating.
In these situations, if you have doubts, the safest thing is to act as if it were hypoglycemia and take fast-acting sugar. Treating a drop that wasn’t real poses no significant risk; ignoring a real drop can have serious consequences.
Causes of hypoglycemia
The causes differ significantly depending on whether the person has diabetes or not.
Hypoglycemia in people with diabetes
It is the most common form and is usually related to an imbalance between medication, diet, and physical activity:
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Excessive insulin dose or hypoglycemic medications like sulfonylureas.
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Skipping a meal or eating fewer carbohydrates than usual.
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Intense or prolonged physical exercise, which increases insulin sensitivity for several hours afterward.
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Alcohol consumption, especially on an empty stomach, since the liver prioritizes alcohol metabolism over glucose production.
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Changes in routine, such as travel, intense stress, intercurrent illnesses, or time zone changes.
90% of hypoglycemia cases in people with diabetes are caused by external factors and can be prevented with good health education and proper treatment adjustment.
Hypoglycemia in people without diabetes
Although less common, it also occurs. Its main causes are:
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Prolonged fasting or extreme calorie restriction.
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Excessive alcohol consumption.
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Certain medications such as beta-blockers, quinolones, or high doses of salicylates.
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Liver, kidney, or adrenal diseases.
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Insulin-producing tumors (insulinoma), very rare. Also previous gastric surgeries.
Types of hypoglycemia
Not all hypoglycemias are the same. Knowing the type helps better understand their causes and the most appropriate treatment in each case.
Diabetic hypoglycemia
It is the best known. It occurs in people with type 1 or type 2 diabetes who use insulin or certain oral medications. A person with type 1 diabetes can experience episodes of low blood sugar up to twice a week on average. It is essential that both the patient and their household members know how to recognize and treat it.
Reactive or postprandial hypoglycemia
The reactive hypoglycemia is the one that occurs between 2 and 4 hours after eating, especially after consuming foods rich in fast-absorbing carbohydrates. It happens because the pancreas secretes more insulin than necessary in response to the meal, causing blood glucose to drop excessively shortly after.
It is more common in people without diabetes and can go unnoticed for a long time. Its typical symptoms appear after eating: sudden hunger, dizziness, irritability, palpitations, and intense fatigue.
Treatment is mainly based on dietary changes: eating smaller, more frequent meals, reducing fast-absorbing carbohydrates, and prioritizing foods with a low glycemic index. In cases related to chronic stress, emotional management also plays an important role.
Neonatal hypoglycemia
The neonatal hypoglycemia affects newborns and is the most common metabolic disorder at this stage of life. It occurs because the baby’s mechanisms for regulating blood sugar are not yet mature and their glycogen stores are limited.
The highest risk groups are:
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Premature babies or those with low birth weight (under 2,500 g).
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Children of mothers with diabetes mellitus, especially if poorly controlled.
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Babies large for their gestational age (over 4,000 g).
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Newborns with hypothermia, perinatal asphyxia, or other birth complications.
The symptoms are nonspecific: the baby may be irritable, limp, have difficulty feeding, tremors, or episodes of apnea. In many cases, there are no visible symptoms. Therefore, routine blood sugar monitoring is performed in at-risk groups from the first hours of life.
Treatment consists of starting feeding early (ideally within the first hour of life) and, if hypoglycemia persists or is severe, administering glucose intravenously under medical supervision.
Nocturnal hypoglycemia
It occurs during sleep and is especially hard to detect because the person does not wake up or notice the usual symptoms. It may show up the next day as a morning headache, unexplained tiredness, or the feeling of having slept poorly for no apparent reason. Using continuous glucose monitors (CGM) with alarms is especially helpful for detecting it in high-risk individuals.
What type of diabetes is hypoglycemia?
It is a common question that deserves a clear answer: hypoglycemia is not a type of diabetes. It is a complication or side effect of diabetes treatment, especially type 1 diabetes and certain treatments for type 2 diabetes. It can also occur in completely healthy people, unrelated to diabetes.
Hypoglycemia and hyperglycemia: what is the difference?
They are the two extremes of blood sugar control. While hypoglycemia involves a glucose level that is too low (below 70 mg/dL), the hyperglycemia is the opposite situation: an excess of glucose in the blood (above 126 mg/dL fasting according to diabetes diagnostic criteria).
Both can be dangerous, but hypoglycemia requires immediate action because the brain can be affected within minutes. Hyperglycemia, although also serious in the long term, usually allows more time before becoming an emergency.
How hypoglycemia is treated
Treatment varies depending on the severity of the episode and the person's situation. Acting quickly and correctly is essential to prevent mild hypoglycemia from becoming an emergency.
Treatment for mild or moderate hypoglycemia: the 15/15 rule
If you are conscious and can swallow, the recommended guideline is the 15/15 rule:
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Take 15 grams of fast-absorbing carbohydrates.
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Wait 15 minutes.
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Measure your glucose again.
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If it remains below 70 mg/dL, repeat the process.
To raise blood sugar quickly, the most commonly used options are: a glass of natural fruit juice, three or four glucose tablets, a packet of sugar dissolved in water, or a sugary non-carbonated drink. Check our complete guide on how to raise blood sugar quickly (/subir-azucar-rapido/) to learn about all available options and which act fastest.
Once glucose exceeds 70 mg/dL, it is important to have a snack that includes slower-absorbing carbohydrates (such as bread, whole-grain crackers, or fruit) to prevent blood sugar from dropping again in the following minutes.
Specific products to treat hypoglycemia
There are solutions specifically designed for this purpose that offer a precise and known dose of glucose, which facilitates treatment and reduces the margin of error:
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Glucose gels: very fast absorption, ideal when the person has difficulty swallowing or is drowsy. It can be applied directly to the mucous membrane of the mouth without the need to swallow.
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Glucose tablets: convenient to always carry with you. Each tablet contains a fixed dose (usually 4 g of glucose), allowing precise control of how much is taken.
Both options have an advantage over conventional foods or drinks: they contain no fats or proteins, allowing glucose to be absorbed more quickly and predictably.
Treatment of severe hypoglycemia
When the person is unconscious, very confused, or cannot swallow safely, nothing should be attempted to be given by mouth. The options in this case are:
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Glucagon: hormone that raises blood glucose levels. It can be administered as an intramuscular injection or via a nasal spray. People with high-risk diabetes should always have a glucagon kit available and their caregivers should know how to use it.
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Intravenous glucose: administered by healthcare personnel in a hospital emergency context.
If the person loses consciousness or has seizures, call 112 immediately.
How to prevent low blood sugar
Prevention is always the best treatment. These are the most effective strategies according to each person's profile:
If you have diabetes:
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Do not skip meals or snacks and maintain regular eating schedules.
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Check your glucose before and after physical exercise, especially if it is intense or prolonged.
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Adjust your insulin dose with your doctor when you change your routine (travel, illness, increased activity).
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Always carry a fast-acting source of glucose with you.
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Educate your family or close contacts on what to do if you have a severe low.
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Consider using a continuous glucose monitor (CGM) with alarms if you have frequent episodes or asymptomatic hypoglycemia.
If you do not have diabetes but experience lows:
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Avoid prolonged fasting and large amounts of refined carbohydrates.
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Reduce alcohol consumption, especially on an empty stomach.
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Distribute meals into 5-6 small servings throughout the day to maintain stable glucose levels.
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Consult your doctor if episodes are frequent to rule out underlying causes such as reactive hypoglycemia or hormonal disorders.
Frequently asked questions about hypoglycemia
Is hypoglycemia always a symptom of diabetes?
No. Although it is much more common in people with diabetes who use insulin or certain medications, it can also affect healthy people due to fasting, intense exercise, alcohol consumption, or other medical causes.
Can I have hypoglycemia if I have type 2 diabetes?
Yes, especially if you take insulin or sulfonylureas. People with type 2 diabetes who only control their glucose with diet or metformin have a much lower risk of hypoglycemia.
What happens if hypoglycemia is not treated?
Untreated hypoglycemia can progress to severe confusion, seizures, loss of consciousness, and in extreme cases, brain damage or death. That is why it is crucial to act quickly at any suspicion.
How long does it take for blood sugar to rise after taking glucose?
With fast-acting carbohydrates like glucose gel or tablets, improvement is usually noticed within 10-15 minutes. If there is no improvement after 15 minutes, the dose should be repeated. If the situation does not improve after two rounds, seek immediate medical attention.
Can hypoglycemia occur at night?
Yes, nocturnal hypoglycemia is more common than you might think, especially in people with type 1 diabetes. It can go completely unnoticed during sleep. Symptoms upon waking such as headache, sweat-soaked clothes, or feeling exhausted after sleeping may be signs.
Prevent hypoglycemia from becoming a problem
Hypoglycemia is a common condition that can range from mild discomfort to a medical emergency. Recognizing its symptoms, understanding its causes, and knowing exactly how to act, whether you experience it or someone around you does, is essential for managing it safely and without losing control.
If your episodes of low blood sugar are frequent, always consult your medical team to adjust the treatment and, if you have diabetes, make sure to always have fast-acting glucose sources on hand. Being prepared is the best way to ensure a low blood sugar episode doesn't catch you off guard.
