Hypo Symptoms: How to Spot and Treat Low Blood Sugar

A striking fact: low blood sugar can come on fast — in minutes. That sudden crash is what people mean by a "hypo." Recognizing it early keeps you safe.

Common signs include sweating, trembling, fast heartbeat, lightheadedness, hunger, blurred vision, and irritability. You might feel shaky and weak, or confused and unable to think clearly. Some people get headaches or a tingling around the mouth. Night-time hypos can wake you sweating or with a bad dream.

For people on insulin or sulfonylureas, hypos are the most common danger. Skipping meals, exercising more than usual, drinking alcohol, or taking an extra dose can trigger one. Illness that reduces appetite or vomiting also raises the risk.

Treating a hypo right away

Act fast when you suspect a hypo. Check your blood glucose if you can. If it's below 70 mg/dL (3.9 mmol/L), treat immediately. If you don't have a meter, still treat if symptoms are clear. Use about 15–20 grams of fast-acting carbs: glucose tablets, a small juice box, regular soda (not diet), or a tablespoon of honey or sugar. Wait 10–15 minutes, then recheck. If it's still low, repeat treatment.

If the person is drowsy, confused, or can't swallow, don't give food by mouth. Call emergency services. For insulin users, emergency kits with glucagon are lifesavers. Modern nasal glucagon is available in some places and works without injections. Make sure family or friends know how to use it.

Preventing hypos and staying safe

Preventing hypos is as important as treating them. Carry fast carbs with you. Eat regular meals and snacks as advised. When you plan extra exercise, reduce insulin or eat extra carbs according to your care plan. Limit alcohol, or never drink on an empty stomach. Keep a log of lows to spot patterns and discuss them with your healthcare team.

Teaching others about your hypo signs helps. Wear an ID bracelet if you have diabetes so responders know how to help. Show partners, coworkers, and carers how to check glucose and use glucagon.

Differentiating hypos from panic attacks or other issues matters. Panic attacks can share sweating and fast heart rate but usually don't cause confusion or very low glucose readings. Always check sugar when in doubt.

Talk to your doctor if hypos happen more than twice a week, or if you have "hypoglycemia unawareness" — no warning symptoms before a severe low. Adjusting medications, changing meal timing, or using continuous glucose monitors can prevent dangerous drops.

Quick recap: learn the signs, treat fast with 15–20 grams of quick carbs, carry supplies, and get help when needed. Small habits make a big difference in avoiding scary lows.

When to call for help

Call for emergency help if someone becomes unconscious, has a seizure, or cannot be roused. If glucagon is given, still get medical attention right away. If you're unsure about symptoms or lows happen after treatment, seek care. Your clinic can review doses and suggest changes like a lower evening insulin dose or a CGM to reduce future risk. Keep a simple plan.