Low Blood Sugar (Hypoglycemia) First Aid: Signs, the 15-15 Rule, Glucagon and When to Call 911

Quick answer: if someone with diabetes is shaky, sweaty, confused or acting unusually and can swallow safely, give 15 grams of fast-acting carbohydrate, such as 4 ounces (half a cup) of juice or regular soda, glucose tablets or gel as labeled, or a tablespoon of sugar or honey. Recheck blood sugar after 15 minutes and repeat if it is still below 70 mg/dL, then have a snack or meal once it rises. This is the American Diabetes Association’s “15-15 rule.” If the person is unconscious, having a seizure or cannot swallow, do not put anything in their mouth: give prescribed glucagon if available and you know how, call 911 and place them on their side.

Low blood sugar can turn a normal afternoon into an emergency in minutes. A coworker suddenly sounds confused, a family member breaks into a sweat or a child becomes irritable and pale. For people who use insulin or certain diabetes medicines, lows are common, and most are easy to treat when caught early. Knowing the signs and the simple steps for treatment can prevent a dangerous drop. This guide is part of our emergency first aid guide.

Guidance in this article comes from the American Diabetes Association (ADA), the National Institute of Diabetes and Digestive and Kidney Diseases (NIDDK), MedlinePlus and the U.S. Food and Drug Administration (FDA). It is general information, not a substitute for medical care or an individual diabetes plan. People with diabetes should follow the treatment plan from their health care team.

What Low Blood Sugar Is

Hypoglycemia means blood glucose has fallen below a healthy level. The ADA uses these levels:

Level	Blood glucose	What it means
Level 1	Below 70 mg/dL and at or above 54 mg/dL	Low; treat promptly
Level 2	Below 54 mg/dL	Clinically significant low; treat right away
Level 3	Any level with severe confusion or unconsciousness	Severe; person needs help from someone else

Low blood sugar is most common in people taking insulin or medications called sulfonylureas, which increase insulin release. It can also occur after some types of stomach surgery or, rarely, with other medical conditions.

Common Causes

• Taking too much insulin or diabetes medicine
• Skipping or delaying meals
• Eating fewer carbohydrates than planned
• Exercising more than usual
• Drinking alcohol, especially without food
• Illness, vomiting or diarrhea

Signs and Symptoms

Early Signs

• Shakiness or trembling
• Sweating and clamminess
• Fast heartbeat
• Hunger
• Anxiety or irritability
• Dizziness or lightheadedness
• Pale skin
• Tingling lips

Worsening Signs

• Confusion or trouble concentrating
• Slurred speech
• Blurred vision
• Clumsiness or poor coordination
• Unusual behavior, which can be mistaken for intoxication
• Weakness or drowsiness

Severe Signs

• Seizures
• Unresponsiveness or loss of consciousness

Some people, especially those who have had diabetes a long time or have frequent lows, do not feel early symptoms. This is called hypoglycemia unawareness, and it makes lows more dangerous. Lows can also happen during sleep, sometimes causing nightmares, sweating through sheets or waking with a headache.

First Aid: The 15-15 Rule

If the person is awake and able to swallow:

1. Check blood sugar with a meter or continuous glucose monitor if possible. If you cannot check, treat anyway when symptoms suggest a low.
2. Give 15 grams of fast-acting carbohydrate.
3. Wait 15 minutes, then recheck.
4. Repeat if blood sugar is still below 70 mg/dL.
5. Eat a snack or meal once blood sugar is back in range, especially if the next meal is more than an hour away.

Fast-Acting Carbs With About 15 Grams

• Glucose tablets or gel, following the label for a 15-gram dose
• 4 ounces (half a cup) of fruit juice
• 4 ounces of regular soda, not diet
• 1 tablespoon of sugar, honey or corn syrup
• Hard candies or jelly beans, as listed on the package nutrition label

Avoid using chocolate, peanut butter or other high-fat foods first, since fat slows how quickly sugar is absorbed. Children may need smaller amounts; follow their diabetes care plan.

If the Person Cannot Swallow or Is Unconscious

Severe low blood sugar is an emergency.

1. Do not give food or drink. The person could choke.
2. Give glucagon if it has been prescribed and you know how to use it.
3. Call 911. Our guide on how to call 911 and what to say helps you give clear information.
4. Place the person on their side in the recovery position to keep the airway clear, especially if they vomit.
5. Stay with them until help arrives.

If the person has a seizure, protect them from injury and do not restrain them; our guide to seizure first aid explains the steps.

Using Glucagon

Glucagon is a hormone that raises blood sugar quickly by signaling the liver to release stored glucose into the bloodstream, which is why it works even when a person cannot eat or drink. It is available by prescription in several forms:

• Nasal powder sprayed into one nostril
• Prefilled autoinjector or syringe injected into the outer thigh, upper arm or abdomen
• Traditional kits that require mixing powder and liquid before injecting

Follow the instructions on the device. After giving glucagon, the person may vomit, so turn them on their side. They should wake within about 15 minutes. Once awake and able to swallow, give a fast-acting carb followed by a snack. Call 911 if they do not respond, and let medical providers know glucagon was given.

People at risk of severe lows should keep glucagon at home, work, school and in their bag, and family, coworkers and teachers should know where it is and how to use it.

When to Call 911

• The person is unconscious, having a seizure or cannot swallow
• Symptoms do not improve after two or three rounds of treatment
• You do not have glucagon and the person cannot take sugar by mouth
• The person does not have known diabetes and has severe symptoms
• You are not sure what is wrong

Low blood sugar can look like a stroke, intoxication or fainting. When in doubt, call.

Low Blood Sugar in Specific Situations

While Driving

A low behind the wheel can be as dangerous as impaired driving. The ADA advises people who use insulin or other medicines that can cause lows to check blood sugar before driving and on long trips. If you feel symptoms while driving, pull over safely, turn off the car, treat the low and wait until blood sugar is back in range and you feel fully alert before driving again. Keep fast-acting carbs within reach in the car.

During Exercise

Physical activity lowers blood sugar, sometimes for hours afterward. Check before, during long workouts and after exercise. Carry glucose tablets or a sports drink. If symptoms start, stop exercising, treat and wait before continuing.

At Night

Overnight lows can be hard to notice. Signs include nightmares, crying out, damp sheets from sweating, restless sleep or waking with a headache and feeling tired. Checking blood sugar at bedtime, eating a snack if advised by your care team and using a continuous glucose monitor with alarms can help.

In Children

Children may not recognize or explain a low. They may seem cranky, unusually quiet, pale, shaky or have trouble focusing in class. A written diabetes medical management plan from the child’s care team tells schools, coaches and babysitters what to watch for, how much carbohydrate to give and when to use glucagon. Make sure caregivers know where supplies are kept.

With Alcohol

Alcohol can lower blood sugar for many hours, including overnight, and the symptoms of a low can look like intoxication. Friends may miss a serious low, assuming the person is just drunk. Eating while drinking, checking blood sugar and wearing medical ID can prevent dangerous mix-ups.

Diabetes Supplies in Emergencies and Power Outages

Storms, outages and evacuations can disrupt access to medicine and food. Prepare by keeping:

• At least a week or two of medications and testing supplies, if your plan and insurance allow
• Glucose tablets or gel and shelf-stable snacks such as crackers and juice boxes
• Glucagon, checking expiration dates regularly
• Extra batteries or charging options for meters, pumps and monitors
• A cooler and cold packs for insulin if the power goes out
• A written list of medicines, doses, doctors and pharmacy information

The FDA notes that during emergencies, insulin may be kept unrefrigerated, at temperatures between 59 and 86 degrees F, for up to 28 days and still work, though storage times vary by product. Keep insulin out of direct sunlight, hot cars and freezing temperatures, and replace it as soon as you can if it was exposed to extreme heat or cold. Our guide to an apartment emergency kit shows how to fit medical supplies into a small space.

Helping Someone at Work or in Public

You may not know whether a stranger or coworker has diabetes. Look for a medical ID bracelet, necklace or wallet card, or a glucose monitor on the arm or abdomen. Ask simply, “Do you have diabetes? Do you need sugar?” Many people carry glucose tablets or candy and can tell you where to find them. Stay with the person until they are feeling better, and encourage them to eat a snack once their blood sugar comes up. If they are confused and refuse help, call 911 rather than leaving them alone.

Teaching Family and Friends

People with diabetes can make emergencies safer by showing others what to do. Explain your usual symptoms, where you keep fast-acting carbs and glucagon and how to use your glucagon device. Practice with a trainer device if one is available. Share your care plan with roommates, partners and close coworkers. A short, calm conversation ahead of time can make a big difference in a real emergency.

Preventing Lows

• Follow the medication and meal plan from your health care team.
• Check blood sugar more often during exercise, illness and travel.
• Carry fast-acting carbs at all times.
• Eat when drinking alcohol, and check blood sugar before bed.
• Wear medical ID that says you have diabetes.
• Talk with your doctor about frequent lows, which may mean medication needs adjusting.

Low vs. High Blood Sugar

High blood sugar, or hyperglycemia, can also cause problems, and the two are sometimes confused. Highs usually develop over hours or days with thirst, frequent urination, tiredness and blurred vision. Very high blood sugar can lead to diabetic ketoacidosis, with nausea, vomiting, fruity-smelling breath and fast breathing, which needs emergency care. Lows come on faster, often within minutes, with shakiness, sweating and confusion.

If you are unsure which problem someone has and they can swallow, a small amount of sugar is usually recommended. It can quickly reverse a low, and the brief extra sugar is unlikely to cause harm if the problem turns out to be high blood sugar. Then check blood sugar and get medical help as needed.

After a Low

Once blood sugar is back in range, the person may feel tired, hungry or have a headache for a while. Encourage rest and a balanced snack or meal with protein and carbohydrates. Recording the episode, including the reading, what might have caused it and how it was treated, helps a health care team spot patterns. Anyone who needed glucagon or emergency care should let their doctor know promptly, since medications may need adjusting. Replace any used glucagon or glucose supplies right away so they are ready for next time.

Frequently Asked Questions

What is the fastest way to raise low blood sugar?

Glucose tablets or gel, juice or regular soda work quickly. Follow the 15-15 rule.

What blood sugar is too low?

Below 70 mg/dL is considered low, and below 54 mg/dL is a more serious low that needs immediate treatment.

Can I give someone with low blood sugar candy?

Yes, if they can swallow safely. Hard candy or jelly beans work; avoid chocolate as a first choice.

What should I do if someone with diabetes passes out?

Do not give food or drink. Use glucagon if available, call 911 and turn them on their side.

Can people without diabetes get low blood sugar?

It is less common but possible, and it should be evaluated by a doctor.

How long does it take to recover from low blood sugar?

Many people feel better within 15 to 20 minutes of treatment, though fatigue can linger.