What Is Hypoglycemia?

Hypoglycemia is a condition where blood sugar drops below 70 mg/dL (3.9 mmol/L), most commonly in people with diabetes who take insulin or certain medications. It’s not just a minor inconvenience-it’s a medical event that can lead to confusion, seizures, or even unconsciousness if not treated quickly. Even if you don’t have diabetes, low blood sugar can happen, but it’s far less common. For people managing diabetes, especially Type 1, hypoglycemia is the most frequent acute complication. About 47% of Type 1 diabetes patients and 33% of insulin-treated Type 2 patients experience at least one episode per year.

How Do You Know You’re Having a Low?

Your body gives you signals before things get dangerous. These come in two types: physical and mental.

• Physical symptoms: Shaking, sweating, rapid heartbeat, hunger, dizziness. These happen because your body releases adrenaline to try to raise your blood sugar. Your heart might race to over 100 beats per minute, and you might feel clammy even if it’s not hot.
• Mental symptoms: Blurry vision, trouble concentrating, confusion, irritability, slurred speech. These are more serious. They mean your brain isn’t getting enough glucose. At 55 mg/dL, you might start seeing double. Below 50 mg/dL, you could lose coordination. Below 45 mg/dL, you may pass out.

Here’s the catch: after years of diabetes, some people lose these warning signs. This is called hypoglycemia unawareness. It affects about 25% of long-term Type 1 patients. Without shaking or sweating, they don’t realize their blood sugar is crashing until it’s too late.

What Causes Low Blood Sugar?

In people with diabetes, the most common cause is an imbalance between medication, food, and activity.

• Too much insulin or medication: 73% of episodes happen because someone took more insulin than needed-maybe they miscalculated their carb intake or injected too much.
• Not eating enough: Skipping meals, eating less than planned, or delaying a snack can trigger a drop. Even a light lunch after a morning insulin dose can be risky.
• Exercise without adjustment: Physical activity makes your body use glucose faster. A 45-minute walk or bike ride can drop blood sugar by 30-50 mg/dL if you don’t eat extra carbs or reduce insulin.
• Alcohol: Especially on an empty stomach, alcohol blocks the liver from releasing stored glucose. One drink can cause a drop hours later-often while sleeping.
• Delayed digestion: After bariatric surgery, food moves too quickly into the intestines, causing a sugar spike followed by a crash. This is called reactive hypoglycemia.

Non-diabetics rarely get hypoglycemia, but when they do, it’s often tied to rare conditions like insulinomas (tumors that make too much insulin) or organ failure.

How to Treat It-Fast

Time matters. If your blood sugar is below 70 mg/dL, you need to act within 15 minutes.

The standard method is the 15-15 rule:

1. Take 15 grams of fast-acting carbohydrates. Examples: 4 glucose tablets, 1/2 cup of fruit juice, 1 tablespoon of honey, or 6-8 hard candies.
2. Wait 15 minutes.
3. Check your blood sugar again.
4. If it’s still below 70 mg/dL, repeat the process.

This works in 78% of mild to moderate cases. But if you’re too confused to eat, or you’re passing out, this won’t help. That’s when you need glucagon.

Glucagon is a hormone that tells your liver to release stored sugar. It comes as a nasal spray (Zegalogue) or injection. A single 1 mg nasal dose works in 94% of cases within 15 minutes. It’s easy to use-even someone with no medical training can give it. If you have diabetes and take insulin, make sure your family, coworkers, or friends know where your glucagon kit is and how to use it.

What Not to Do

Some common mistakes make things worse.

• Don’t use chocolate or candy bars. They have fat and protein, which slow sugar absorption. You need fast-acting carbs-no delays.
• Don’t wait to see if it gets better. Every minute counts. A drop from 60 to 40 mg/dL can happen in under 10 minutes.
• Don’t drive when you feel low. At 50 mg/dL, your reaction time is as impaired as if you had a 0.08% blood alcohol level-the legal limit for drunk driving.
• Don’t assume your CGM is always right. Sensors can lag. If you feel low but your monitor says 98 mg/dL, treat it anyway. Real blood sugar can be 40 mg/dL while the sensor reads high.

How to Prevent Low Blood Sugar

Prevention is better than treatment-and it’s possible.

• Use a continuous glucose monitor (CGM). CGMs track your sugar levels every 5 minutes. Most can alert you when your sugar is dropping too fast. Studies show they reduce hypoglycemia time by 35%. Newer models even predict drops 45 minutes ahead.
• Adjust insulin for activity. If you’re going to exercise for more than 45 minutes, reduce your basal insulin by 20-50%. Eat 15-30g of carbs before or during.
• Check your sugar before bed. Nighttime lows are dangerous. If your sugar is below 100 mg/dL, have a small snack with protein and carbs. Consider setting your CGM to alert you at 60 mg/dL while sleeping.
• Carry glucose everywhere. Keep glucose tablets or juice boxes in your car, purse, desk, and gym bag. Don’t rely on your phone to remember.
• Teach people around you. 54% of people with hypoglycemia have been mistaken for being drunk. Make sure coworkers, friends, or teachers know what to do if you collapse.
• Review your insulin-to-carb ratio. If you’re frequently low after meals, your ratio might be off. Work with your diabetes educator to fine-tune it.

Technology Is Changing the Game

In 2023, new tools made prevention easier.

• Predictive low-glucose suspend systems (like Guardian 4) automatically pause insulin delivery if your sugar is about to drop. They reduce nighttime lows by 44%.
• Artificial pancreas systems (like Tandem Control-IQ) adjust insulin automatically based on real-time data. Users spend 3.3 fewer hours per week below 54 mg/dL.
• Glucagon nasal spray replaced messy injections. It’s now FDA-approved, easier to store, and works faster.

These aren’t just gadgets-they’re lifesavers. But they’re not perfect. Alarm fatigue is real: 41% of CGM users turn off alerts because they’re too frequent. That’s why education still matters.

Who’s at Highest Risk?

• People with Type 1 diabetes: Average of 19 episodes per month. Nocturnal lows are common.
• Older adults (>65): Often show atypical symptoms like falls, confusion, or dizziness-mistaken for dementia. Each severe episode raises dementia risk by 4.7%.
• Those with hypoglycemia unawareness: 25% of long-term Type 1 patients. Their body no longer sends warnings.
• People who’ve had severe hypos before: One episode doubles the chance of another.

And here’s a scary fact: hypoglycemia contributes to 6% of sudden deaths in Type 1 diabetics under 40-known as the "dead-in-bed" syndrome. You go to sleep fine. You don’t wake up.

When to Call for Help

Call 911 or get emergency help if:

• You or someone else is unconscious or having a seizure.
• Glucagon was given but there’s no improvement after 15 minutes.
• You’ve had multiple low episodes in 24 hours with no clear cause.

Emergency rooms see about 100,000 hypoglycemia cases a year in the U.S. Many are misdiagnosed as stroke or intoxication. If you’re with someone who’s confused and sweating, don’t wait-treat for low blood sugar first.

Final Thoughts

Hypoglycemia isn’t something you just "deal with." It’s preventable. With the right tools-CGMs, glucagon, education, and smart habits-you can live without fear of crashing. The goal isn’t perfect numbers. It’s staying safe. If you’re managing diabetes, your next step isn’t more insulin. It’s making sure you never have to ask, "What do I do if I feel like this?"

Next Steps

• If you have diabetes and take insulin: Get a CGM if you don’t have one. Set low alerts at 60 mg/dL.
• Keep glucagon in your home, car, and work bag. Show someone how to use it.
• Track your low episodes: When? Why? What helped? This helps you spot patterns.
• Ask your doctor about your insulin-to-carb ratio and basal rates. They might need adjusting.
• If you’ve had a severe low in the past year, ask about a referral to a diabetes educator. Specialized training reduces severe hypos by 37%.