How to Spot Low Blood Sugar Warning Signs

Spotting low blood sugar, or hypoglycemia, warning signs involves looking for a range of symptoms and identifying behaviors. Slightly low blood sugar (under 70 mg/dl) might produce nausea, nervousness, or irregularities of your pulse. Moderate low blood sugar (under 55mg/dl) warning signs include mood changes, headaches, and mental difficulties. Severely low blood sugar (35 – 40 mg/dl) could lead to fainting, seizures, and hypothermia.^[1] Hypoglycemia is a particular risk for those with diabetes and can develop into an emergency situation if not treated. Work to prevent low blood sugar by eating a snack, especially before and after exercise, and managing your blood sugar levels if you are diabetic.

EditSteps

EditIdentifying Mild Hypoglycemia

Look for stomach troubles. If you have low blood sugar, you might experience a loss of appetite or nausea.^[2] Nausea is a feeling of queasiness or an upset stomach. In serious but rare cases, you might actually vomit due to your nausea.^[3]
Notice feelings of hunger. Hunger is always partially a result of having low blood sugar. The lower your blood sugar, the hungrier you will feel. Mild hypoglycemia may in fact cause feelings of extreme hunger.^[4]
- If this is your only warning sign of low blood sugar, you can probably remedy the situation by grabbing a snack like a banana.
Monitor for feelings of nervousness. If you feel nervous or jittery, you could have low blood sugar. Look for involuntary motions like a bouncing leg when seated, a need to pace back and forth, or a racing heart to detect feelings of nervousness.^[5]
- More extreme jitters or bodily trembling might also occur.
Check for cold, wet, or clammy skin. Sweaty or clammy skin might indicate hypoglycemia. To spot cold, wet, or clammy skin, lay your hands on your skin. Alternately, look for a pallor or sheen of sweat.^[6]
- If you have nocturnal hypoglycemia – that is, low blood sugar while sleeping – you might wake up sweaty in the morning or in the middle of the night.
Monitor for a rapid heart rate. A racing heart (tachycardia) could indicate low blood sugar. Heart palpitations (any irregular heartbeat, such as pauses, skipping a beat, or rapid heartbeat) may occur briefly.^[7] Tachycardia describes a racing heart and is common in cases of mild hypoglycemia.^[8]
- The best way to diagnose heart palpitations or other irregularities is by getting evaluated by a doctor. If palpitations occur regularly there may be an underlying issue other than hypoglycemia, so it's important to get this checked.
- You could also discern heart palpitations by staying conscious of your body’s feedback mechanisms. A racing heart might manifest, for instance, as a beating in your chest.
- Tachycardia often has no symptoms.^[9]

EditIdentifying Moderate Low Blood Sugar

Look for mood changes. Mood changes could take many forms. Any shift away from your normal level of anxiety, anger, restlessness, or irritability could be a sign of low blood sugar.^[10] If you feel a sudden change in your mood without an easily identifiable cause, it could be due to low blood sugar.^[11]
- If you or the person you’re evaluating for low blood sugar is normally irritable, anxious, and short-tempered, looking for changes in their mood will not be an ineffective mode of identifying low blood sugar warning signs.
Check for cognitive difficulties. Cognitive difficulties refer to a suite of mental problems, including confusion, attention problems, and a general inability to think clearly.^[12] If you or someone you’re evaluating demonstrates difficulty staying mentally focused in a sustained way, they might have low blood sugar.^[13]
Look for headaches. These headaches could occur in your temples, on top of your head, or at the back of your head. When related to low blood sugar, they might be accompanied by dizziness or blurred vision.^[14]
- If you have nocturnal hypoglycemia — that is, low blood sugar while sleeping — you might experience headaches in the morning when you wake.^[15]
Look for weakness. A feeling of fatigue and tiredness often accompanies low blood sugar. If you need to lie down, sit down, or relax due to low energy levels, you might have low blood sugar.^[16]
- Nocturnal hypoglycemia is also often accompanied by waking up tired, rather than refreshed, as you should after getting a full night’s rest.
Look for a lack of coordination. As your blood sugar level crashes, you will lose the ability to control your motor functions. Speech will become slurred and you might become clumsy and stagger about, unable to walk properly.^[17]

EditIdentifying Serious Hypoglycemia

Look for seizures. Seizures or convulsions occur when your blood sugar gets excessively low. If you have seizures, get medical attention immediately, as this is a serious low blood sugar warning sign. Common indications that you’re having a seizure include:^[18]
- Uncontrollable head and eye movement
- Sweating and anxiety
- Unusual body posturing
- Difficulty speaking
Check for a loss of consciousness. If you faint or even just feel drowsy, it could be due to low blood sugar.^[19] And in extreme cases, you might slip into a coma — a prolonged period of unconsciousness from which it can be difficult to awaken.^[20]
- You can identify a loss of consciousness by suddenly waking up on the floor or in another unusual position that you can’t remember putting yourself in.
- If a diabetic has lost consciousness, inject them with glucagon (a hormone used to raise blood sugar levels) if you know how. Call emergency services immediately.^[21] Do not attempt to give an unconscious person food or drink.
- Alternately, call an ambulance if you do not have glucagon, if you do not know how to inject glucagon, or if the injection has proven ineffective after 10 minutes.
Check for low body temperature. If possible, take your temperature to spot one of the extreme low blood sugar warning signs. If your temperature is below 95°F (35°C), you will go into hypothermia, a condition characterized by shivering, then abnormal organ function. Seek medical attention immediately if you have hypothermia.^[22]

EditPreventing Hypoglycemia

Eat regularly. You should eat three meals per day — one when you wake, another towards the middle of the day, and another in the mid-to-late evening. Missing a meal or consuming fewer carbs than your body requires could cause your blood sugar to crash.^[23]
- If you miss a meal or cannot eat a meal, grab a snack like popcorn, trail mix, or a banana.
Eat before and after workouts. Exercise takes a lot of energy, and your blood sugar typically declines after an intense workout. Consume a source of carbs within three hours of your workout, but not within the hour prior to your planned workout. After you’re done working out, have a source of protein and carbs (a protein smoothie, for instance) within 20 minutes to prevent low blood sugar.^[24]
Check your blood sugar. If you have diabetes, check your blood sugar regularly, as directed by your doctor. You can do this using a blood sugar monitoring device. If you do not have a blood sugar monitoring device, consult your doctor for a recommendation regarding the most reliable such device available.^[25]
- Follow manufacturer directions to use the blood sugar monitoring device.
Treat low blood sugar promptly. When you notice signs of low blood sugar, it is important to address it as quickly as possible. You should consume about 15 grams of glucose or simple carbohydrates. Wait 15 minutes, then check your blood sugar again. If you are still hypoglycemic, eat another 15 grams. If your next meal is more than an hour or two away, eat a small snack once your blood sugar has returned to normal. Try the following sources of simple carbohydrates:^[26]
- 4 ounces of juice or soda (not diet)
- 1 tablespoon sugar, honey, or corn syrup
- 8 ounces of nonfat or 1% milk
- Glucose tablets or gel (follow package instructions).
Let your family know of your condition. If your family and friends know you have diabetes, they will be able to help you spot low blood sugar warning signs. By catching your low blood sugar levels early, you could avoid more serious complications associated with low blood sugar.^[27]
- Wear a medical ID bracelet that identifies your condition and carry a medical ID card as well. If you are in an emergency situation and unable to communicate (such as if you fall unconscious), this information can help the emergency medical staff determine treatment.^[28]