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The two emergencies: learn these first

A low is the fast one and needs sugar now. Ketoacidosis is the slow one and needs a hospital. What everyone around a person with type 1 should know.

Type 1 diabetes has two emergencies, and they come before everything else on this site because they are the parts that can hurt someone this week.

Too low — a hypo. Arrives in minutes, below 3.9 mmol/L. Shaky, sweating, pale, confused, irritable, clumsy. Caused by too much insulin for the food or the activity, and by alcohol hours later. Untreated, it goes to seizure and unconsciousness. This is the fast one, and it needs sugar now.

Too high — DKA (diabetic ketoacidosis). Builds over hours. Missed insulin, illness or a pump failure lets ketones build and the blood turn acidic. Stomach pain, vomiting, sweet-smelling breath, fast deep breathing, thirst, drowsiness. It does not fix itself. This is the slow one, and it needs a hospital.

Fast versus slow is the whole mental model. One is treated with sugar in your pocket; the other is treated by going in.

Anyone who spends time with the person — partner, roommate, coworker, coach — should be able to describe both. It takes two minutes to teach.

Sources
  • Diabetes Canada Clinical Practice Guidelines

Last reviewed: September 24, 2026

Education, not medical advice. Every dose, ratio and target belongs with your own diabetes team.