A “diabetic attack” typically refers to one of two opposite emergencies: blood sugar dropping too low (hypoglycemia) or spiking dangerously high (hyperglycemia). They feel very different from each other, but both come on with warning signs your body sends before things get serious. Low blood sugar hits fast, sometimes within minutes, and feels like a surge of adrenaline. High blood sugar builds slowly over hours or days and feels more like a creeping illness. Here’s what each one actually feels like from the inside, what others might notice, and what to do.
Low Blood Sugar: The Adrenaline Rush
Hypoglycemia, when blood sugar drops below 70 mg/dL, is the most common type of diabetic emergency. It’s also the one people usually mean when they say “diabetic attack.” The first thing most people notice is a sudden, jittery shakiness in their hands, almost like drinking too much coffee. Your heart starts beating fast, you break out in a cold sweat, and you feel an intense, urgent hunger that’s hard to ignore. Many people describe a wave of anxiety or irritability that seems to come out of nowhere, with no obvious emotional trigger.
This happens because your body recognizes the drop and floods your system with stress hormones to try to release stored glucose. That hormonal surge is what causes the shaking, sweating, and racing heart. You might also feel dizzy, lightheaded, or notice tingling in your lips, tongue, or cheeks.
If blood sugar keeps falling, the symptoms shift from that adrenaline-like feeling to something more neurological. Your brain is running out of its primary fuel. Thinking becomes foggy. You may struggle to concentrate, find it hard to follow a conversation, or feel confused about where you are. Vision can blur or narrow into tunnel vision. Coordination deteriorates, making you clumsy or unsteady on your feet. Speech may start to slur. At this stage, some people describe feeling “drunk” even though they haven’t had anything to drink.
Below 54 mg/dL, the situation becomes severe. Muscle weakness can make it impossible to eat or drink without help. Seizures, convulsions, and loss of consciousness can follow.
What Low Blood Sugar Looks Like to Others
If you’re with someone having a low blood sugar episode, the earliest visible signs are pale skin, visible sweating, and trembling hands. They may seem suddenly irritable or anxious for no clear reason. As it progresses, the person may act confused, struggle with simple tasks they’d normally do without thinking, move clumsily, or speak in a way that sounds slurred or slow. They might seem dazed or unresponsive. In severe cases, they may have a seizure or pass out entirely.
Low blood sugar can also happen during sleep. The signs are damp sheets or nightclothes from sweating, restless sleep or nightmares, and waking up feeling exhausted, confused, or unusually irritable.
High Blood Sugar: The Slow Build
Hyperglycemia feels completely different. Instead of a sudden jolt, it creeps in over hours or days. The earliest and most noticeable symptoms are extreme thirst that water doesn’t seem to satisfy and needing to urinate far more often than usual. You feel tired, weak, and generally unwell, like the early stages of the flu.
If blood sugar stays elevated and isn’t treated, the body starts breaking down fat for energy and produces acidic byproducts called ketones. This condition, diabetic ketoacidosis (DKA), is more common in people with type 1 diabetes and escalates quickly once it starts. Breathing becomes fast and deep as your body tries to compensate for the acid buildup. Your mouth and skin feel extremely dry. You may develop a headache, muscle stiffness, nausea, vomiting, and stomach pain. One distinctive sign: your breath may take on a fruity or acetone-like smell, similar to nail polish remover.
There’s also a less common but equally dangerous form of high blood sugar crisis called hyperosmolar hyperglycemic syndrome, which tends to affect people with type 2 diabetes. This involves extreme dehydration that draws water out of organs, including the brain. It causes severe confusion, difficulty speaking, problems with movement or muscle function, and can progress to seizures or coma. People experiencing this often appear deeply disoriented or barely conscious.
How Low and High Episodes Feel Different
- Speed of onset: Low blood sugar hits in minutes. High blood sugar develops over hours to days.
- Physical sensation: Low blood sugar feels like an internal alarm going off, with shaking, sweating, and a pounding heart. High blood sugar feels like being sick, with deep fatigue, thirst, and nausea.
- Hunger: Intense hunger is a hallmark of low blood sugar. High blood sugar typically causes nausea and loss of appetite instead.
- Breathing: Low blood sugar doesn’t usually change breathing. DKA causes rapid, deep breaths.
- Smell: Fruity-smelling breath is specific to high blood sugar with ketone buildup. It doesn’t occur with low blood sugar.
What Happens After an Episode
Even after blood sugar returns to a normal range, the body doesn’t bounce back immediately. After a low blood sugar episode, many people feel wiped out, mentally foggy, and disoriented. This “hangover” effect can last for hours. Fatigue and difficulty concentrating are common, and some people describe feeling emotionally drained or shaky well after the numbers have normalized. The brain, having been briefly deprived of its fuel supply, takes time to fully recover.
Recovery from a high blood sugar crisis, especially DKA, generally takes longer. Rehydration and stabilization in a medical setting can take several hours to a day or more, and lingering fatigue and weakness are typical for days afterward.
What to Do During a Low Blood Sugar Episode
If you feel the early warning signs of low blood sugar and can still eat and drink, follow the 15-15 rule: consume 15 grams of fast-acting carbohydrates (about four glucose tablets, half a cup of juice, or a tablespoon of sugar), then wait 15 minutes. Check your blood sugar again. If it’s still below 70 mg/dL, repeat the process until it rises back into your target range.
If someone with diabetes has passed out or is having a seizure, they need emergency medical help immediately. Don’t try to put food or liquid in the mouth of someone who is unconscious or unable to swallow.
Red Flags That Require Emergency Help
Certain symptoms cross the line from manageable to medical emergency. For low blood sugar, these include seizures, loss of consciousness, and confusion severe enough that the person can’t eat, drink, or help themselves. For high blood sugar, the red flags are fruity-smelling breath, vomiting that makes it impossible to keep food or fluids down, and difficulty breathing. Any of these warrant a call to 911. A diabetic coma can result from either extreme, and the window between “feeling off” and losing consciousness can be shorter than people expect.