Why Am I Always Cold? Everyday and Medical Causes

The short answer

You're usually always cold because of everyday things: a chilly room, light clothing, a smaller or leaner build, short sleep, or sweat cooling you after a workout. When the cold lasts for weeks, comes with tiredness, or shows up in odd ways (one cold foot, fingers turning white), a doctor can check for an underactive thyroid, anemia, Raynaud's, circulation problems, or a medicine side effect. Most of these show up on an exam and a simple blood test.

Why do I feel cold when everyone else is fine?

Start with the boring stuff, because it explains a lot. Your body holds its core temperature by squeezing blood vessels in the skin to cut heat loss and by shivering to make more heat (Castellani 2016). How well that works depends on your body size and build, your sex, and your fitness (Castellani 2016). So two people in the same room can honestly feel different temperatures.

Everyday causes worth checking first:

• The room and your clothes. A drafty desk, an air vent overhead, or thin layers will do it. Your hands and feet usually complain first.
• Your build. Smaller, leaner bodies have less insulation and less muscle making heat. Very low body weight can cause cold intolerance on its own (MedlinePlus lists anorexia nervosa as a cause).
• Short sleep. A review of human studies found limited to moderate evidence that a few nights of poor sleep blunt the body's defenses against cold and heat. The research still has gaps, so file this under "can make it worse."
• Early morning. Your core temperature follows a daily rhythm and bottoms out in the early morning, roughly 2 hours before you usually wake. If you get up very early, you meet your body at its coolest.
• Alcohol. A drink can make you feel warm, yet the CDC lists people who drink alcohol among those at higher risk for hypothermia (CDC).

If you want the bigger picture on why the same temperature feels different from day to day, read why the perfect temperature changes.

Why do I feel cold after exercise?

Your core temperature actually stays raised for a while after a hard workout. What chills you is the sweat. Wet skin and damp clothes keep pulling heat away after you've stopped making extra heat. The CDC notes that hypothermia can happen even above 40°F (4°C) when someone gets chilled from rain, sweat, or cold water (CDC). For a normal gym session, that just means you feel clammy and cold. For a long run or hike in cool, wet weather, take it seriously.

Simple fixes: change into dry clothes soon, put on a layer before you cool off, and drink something warm.

Why do women feel colder than men?

The evidence here is real and a bit annoying. Office temperature rules in many buildings rest on a thermal comfort model from the 1960s that uses the metabolic rate of an average man. Kingma and van Marken Lichtenbelt reported that this standard may overestimate a woman's metabolic rate by up to 35% (Kingma 2015). Lower heat production means a room set for the "standard" man can feel cold to many women.

A few health factors also tilt toward women:

• Raynaud's phenomenon affects women more often than men and usually starts before age 30 (NIAMS).
• Iron-deficiency anemia is more common with heavy periods, blood loss in childbirth, and pregnancy (NHLBI).

Cold researchers also list sex, body build, and fitness among the factors that shape how a person responds to cold (Castellani 2016). Your own experience still counts: if you feel cold, you feel cold.

Medical causes a doctor checks

MedlinePlus lists these causes of cold intolerance: anemia, anorexia nervosa, blood vessel problems such as Raynaud's, chronic severe illness, general poor health, a problem with the hypothalamus (the brain's temperature control center), and an underactive thyroid (MedlinePlus). Here's what each looks like in real life.

| Cause | Clues that often come with it | |---|---| | Underactive thyroid (hypothyroidism) | Tiredness, weight gain, dry skin, thinning hair, slow heart rate | | Iron-deficiency anemia | Fatigue, dizziness, pale skin, cold hands and feet | | Vitamin B12 deficiency | Tiredness, pale skin, tingling or pain, trouble walking, memory loss | | Raynaud's phenomenon | Fingers or toes turn white, then blue, then red in the cold | | Peripheral artery disease | One foot colder than the other, leg pain when walking | | Medicines such as beta blockers | Cold hands and feet after starting or changing a dose |

A few notes on the big ones:

• Thyroid. The NIDDK lists "trouble tolerating cold" among the common symptoms of hypothyroidism, along with fatigue and weight gain.
• Iron and B12. If you searched "what vitamin deficiency causes you to feel cold," the honest answer is B12, plus iron (a mineral). Both can cause anemia, which means fewer working red blood cells. The NHLBI lists cold hands and feet as a symptom of iron-deficiency anemia (NHLBI). B12 deficiency is more common in older adults, vegetarians and vegans, and people taking metformin or heartburn medicines.
• Raynaud's. Cold or stress narrows the blood vessels in the fingers and toes. The skin turns pale or white, then blue and numb, then red as blood returns (NIAMS). Primary Raynaud's has no known cause and is the more common form. Secondary Raynaud's comes with conditions like lupus or scleroderma, tends to be more serious, and needs a closer look (NIAMS).
• Circulation. Peripheral artery disease narrows the arteries to the legs. The NHLBI notes that one foot may feel colder than the other.
• Medicines. The NHS lists cold hands and feet as a common side effect of beta blockers. Don't stop a heart or blood pressure medicine on your own. Ask your doctor if the side effect bothers you.

Suddenly feeling cold and shaking without a fever

Shaking chills are your muscles contracting fast to make heat. A sudden bout with a normal thermometer reading usually comes from one of these:

• A cold or wet environment, including sweaty clothes after exercise.
• The start of an infection. MedlinePlus notes that chills often come before a fever shows up. Recheck your temperature in an hour or two.
• Low blood sugar, especially if you take diabetes medicines or skipped a meal. The NIDDK describes feeling shaky or jittery, hungry, dizzy, and confused.
• A panic attack. The NIMH lists sweating, chills, trembling, and a pounding heart among panic attack symptoms.

Shaking with confusion, slurred speech, or drowsiness after cold exposure can signal hypothermia (CDC).

When to see a doctor

Book a regular visit if:

• You've felt cold for weeks and the room or your clothes don't explain it.
• The cold comes with tiredness, weight change, hair loss, heavy periods, or tingling in your hands or feet.
• Your fingers or toes turn white or blue in the cold, or one foot runs colder than the other.
• You started a new medicine and your hands and feet went cold.

Get care quickly if shaking chills come with a stiff neck, confusion, unusual sleepiness, a bad cough, shortness of breath, belly pain, or burning or frequent urination. Those can mean a serious infection.

Call 911 for:

• Signs of hypothermia: shivering with confusion, fumbling hands, memory loss, slurred speech, or drowsiness, or a body temperature below 95°F (35°C) (CDC).
• Chest pain, fainting, or trouble breathing.
• A person who is confused or can't stay awake.

If you run hot instead of cold, see why am I always hot. For cold nights, the best temperature for sleep guide covers bedroom settings.