Why do I get chills without a fever?

A chill is a heat-production reflex: MedlinePlus describes chills as rapid muscle contraction and relaxation - your body's way of generating warmth when it feels cold - and notes they may or may not come with goosebumps. The fever connection is real but looser than people think. Chills often predict a coming fever because the body's thermostat has already turned up before the measured temperature catches up, so shivering can arrive an hour before the fever does. That means some chills-without-fever are simply chills-before-fever - check your temperature again in a few hours if you also feel achy or unwell. But plenty of chills never involve infection at all. Being genuinely cold is the obvious one - MedlinePlus lists cold exposure as a leading cause, and sitting still in a cool room after exercise can do it as your sweat evaporates. Anxiety and adrenaline surges shake the same muscles (the teeth-chattering kind of nerves before a presentation is real physiology). Blood sugar dips, some medicines, and hormonal shifts (including around periods and menopause) can all produce waves of shivering too. The pattern-matching that matters: chills plus feeling ill point toward infection - test, rest, fluids; chills plus shaking, sweating, and hunger in someone with diabetes mean check blood sugar; drenching shivers that recur nightly for weeks, or chills with confusion, a stiff neck, or breathlessness, mean see a doctor promptly. A single episode on a cold evening with no other symptoms needs nothing but a jumper and a hot drink. Pymander is a free AI doctor, 24/7 by text, that can help you read your pattern.