Low blood sugar can be life-threatening if not treated promptly. It’s important to recognize the signs of hypoglycemia early.
Hypoglycemia occurs when blood glucose levels drop too low, leading to symptoms like dizziness, shakiness, lightheadedness, and a rapid heartbeat. Glucose is a vital source of energy for the body. After eating, your body absorbs glucose and stores the extra in muscles and the liver, creating reserves that can be used later when more energy is needed.
Hypoglycemia is defined as having blood glucose levels below 70 milligrams per deciliter (mg/dL). To determine your blood sugar level, you must test your blood.
People with diabetes frequently monitor their blood sugar to avoid both high (hyperglycemia) and low (hypoglycemia) levels. Hypoglycemia is more common among those with type 1 diabetes but can also affect people with type 2 diabetes, especially those taking insulin or certain diabetes medications.
Although less common, hypoglycemia can also occur in people without diabetes. Diet, physical activity, and even weather conditions can influence blood sugar levels. Additionally, those over 65 or with a history of hypoglycemia, kidney disease, heart disease, or cognitive impairment are at higher risk.
Below are the key signs and symptoms indicating blood sugar may be dangerously low.
Fast Heartbeat
When blood glucose drops too low, the body triggers a stress response, activating the sympathoadrenal system. The adrenal glands release norepinephrine, a hormone that causes the heart to beat faster. A faster heartbeat helps deliver more blood — and therefore more glucose — to vital organs like the brain.
Shaking and Jitteriness
The same release of norepinephrine can cause shaking and jitteriness. Norepinephrine acts as both a hormone and a neurotransmitter, affecting brain communication and leading to these sensations.
Nervousness and Anxiety
Norepinephrine also contributes to feelings of nervousness and anxiety. If you start to feel unusually anxious, it’s important to stay calm and check for other signs of low blood sugar.
Irritability and Confusion
Low blood glucose impacts the central nervous system, leading to changes in behavior. This can include irritability, confusion, and impatience. Some people describe this as feeling “hangry” — a combination of hungry and angry.
Dizziness
Inadequate glucose in the bloodstream deprives the brain of energy, causing dizziness or lightheadedness. This can lead to fainting, which carries risks of injury. If dizziness occurs, it’s important to sit down and seek help.
Headache
Without enough glucose, brain cells struggle to function, often leading to a headache. The brain, although only 2% of body weight, consumes a large portion of the body's glucose.
Hunger
Hunger is a natural response to low blood sugar. The body releases acetylcholine, a neurotransmitter that signals the brain to feel hungry. Eating foods rich in carbohydrates can quickly raise blood glucose levels. People managing diabetes often follow the “15-15 Rule,” consuming 15 grams of carbohydrates and waiting 15 minutes to check if blood sugar levels improve.
Tiredness
When the brain lacks enough glucose, fatigue can set in. If you feel more tired than usual along with other symptoms, a blood glucose test can confirm if low sugar is the cause.
Difficulty Speaking
Speech is controlled by the brain, and when the brain doesn't receive enough glucose, speech difficulties can occur. It's important to differentiate between hypoglycemia and other conditions like stroke, which can also affect speech.
Sweating
Sweating is another reaction to low blood sugar, caused by the release of acetylcholine. Excessive sweating, especially when combined with other symptoms, may indicate hypoglycemia. It can occur during the day or at night.
Poor Sleep Quality
Low blood sugar during sleep can lead to serious issues. Symptoms during sleep may include:
- Crying out or yelling during sleep
- Nightmares
- Waking up sweaty with damp clothing and bedding
- Feeling tired, irritable, or confused upon waking
Severe Symptoms
When blood glucose drops below 54 mg/dL, the situation becomes critical. The brain is severely deprived of energy, which can lead to problems walking, blurred vision, unconsciousness, seizures, or even death if untreated.
When To See a Healthcare Provider
Hypoglycemia symptoms must be treated immediately. If you think you’re experiencing low blood sugar, seek medical advice. Understanding the underlying cause helps you and your healthcare provider create an effective treatment plan.
People with diabetes should always carry quick sources of glucose like fruit juice, glucose gel, tablets, or hard candy. In cases where these options are insufficient, glucagon — a hormone available by prescription — can treat severely low blood sugar. Emergency glucagon kits may be recommended for those at risk.
A Quick Review
Low blood sugar is a serious condition that requires immediate action. Recognizing the signs early can save lives. Be aware of hypoglycemia unawareness — when symptoms occur but aren't noticed — as it increases the risk of dangerously low blood sugar.
If you’re at risk, regularly monitor your blood glucose, especially before activities like driving. Frequent episodes of low blood sugar warrant consultation with a healthcare provider for appropriate management.
