Feeling Cold All the Time: Why It Happens

Why some people feel colder than others

Your body keeps its core at about 37 °C (98.6 °F) by making heat through metabolism and muscle activity, and by narrowing blood vessels in the skin to conserve it. Anything that slows metabolism, reduces insulating fat or muscle, lowers oxygen delivery, or disrupts the brain's thermostat makes you feel cold.

Some differences are normal. Women on average report feeling colder than men, partly because of lower muscle mass and hormonal effects on blood vessels. Older adults make less heat and sense temperature less accurately.

Common causes of feeling cold all the time

Underactive thyroid

Hypothyroidism is the classic medical cause. Low thyroid hormone slows metabolism, so you make less heat. Other clues are tiredness, weight gain, dry skin, constipation, thinning hair, slow thinking, puffy face and heavy periods. A TSH blood test confirms it, and daily thyroid hormone treatment usually restores normal warmth within weeks.

Anemia

With iron-deficiency anemia, the blood carries less oxygen, and iron is also needed for heat production and thyroid function. Cold hands and feet, tiredness, pale skin, breathlessness on stairs, brittle or spoon-shaped nails and cravings for ice are typical. Heavy periods, pregnancy, vegetarian diets and gut bleeding are common causes. Vitamin B12 deficiency can cause anemia too, with tingling and numbness.

Low body weight or not eating enough

Fat insulates and food fuels heat production. Very low body weight, strict dieting, intense endurance training and eating disorders such as anorexia nervosa all cause marked cold intolerance, sometimes with fine body hair (lanugo) and slow heart rate.

Poor circulation and Raynaud's phenomenon

Raynaud's phenomenon causes fingers and toes to turn white, then blue, then red in the cold or with stress, with numbness and throbbing as they rewarm. It is common and usually harmless, but can be linked to autoimmune diseases such as scleroderma or lupus. Peripheral artery disease narrows leg arteries, causing cold feet and leg pain when walking, mostly in smokers and people with diabetes.

Lack of sleep and dehydration

Sleep deprivation lowers your core temperature and makes you feel colder. Dehydration reduces blood volume and the body's ability to hold heat.

Medicines

Beta-blockers cause cold hands and feet. Other medicines that can contribute include some migraine medicines, stimulants that narrow blood vessels, and treatments that lower thyroid function.

Less common causes

• Diabetes: nerve damage and poor circulation cause cold, numb feet. Low blood sugar causes sudden cold sweats.
• Pituitary or hypothalamus problems: affect the body's thermostat and hormones.
• Adrenal insufficiency: tiredness, weight loss, low blood pressure, salt craving.
• Chronic kidney disease: anemia and fatigue.
• Infection: feeling cold with shivering as a fever rises. See chills.

Feeling cold but no fever

If you feel cold and your thermometer reads normal, the cause is usually your environment, tiredness, hunger, low body weight, anemia, thyroid problems or circulation. Feeling cold before a fever starts is also common at the start of an infection: check again in an hour or two.

How doctors find the cause

Your doctor will ask how long you have felt cold, whether it is your whole body or hands and feet, and about weight changes, energy, periods, diet, sleep, medicines and color changes in your fingers. They will check your weight, pulse, blood pressure, skin, nails and foot pulses.

Common first tests:

• TSH and free T4 (thyroid)
• Complete blood count and ferritin (anemia and iron stores)
• Blood sugar or HbA1c
• Vitamin B12, kidney function, and sometimes cortisol

What helps

Treating the cause is what fixes cold intolerance. Meanwhile:

• Dress in layers, and keep your hands, feet and head covered. Thin layers trap heat better than one thick one.
• Eat regular meals that include protein and enough calories. Do not skip breakfast.
• Stay active. Muscle activity generates heat, and regular exercise improves circulation.
• Drink enough fluids. Warm drinks help in the short term.
• Sleep 7 to 9 hours.
• Stop smoking, which narrows blood vessels.
• For Raynaud's, keep the whole body warm, not just the hands, and use gloves before going into the cold.

Frequently asked questions

Why am I always cold when others are warm?

Common reasons are an underactive thyroid, anemia, low body weight, poor sleep, Raynaud's phenomenon or older age. Women tend to feel colder than men. If you also feel tired, have gained or lost weight, or notice hair or skin changes, ask your doctor for thyroid and blood count tests.

What deficiency makes you feel cold?

Iron deficiency is the most common, causing anemia and cold hands and feet. Vitamin B12 deficiency can also cause anemia and numbness. Not eating enough calories overall makes you feel cold too. Thyroid hormone deficiency (hypothyroidism) is the most common hormonal cause.

Can anxiety make you feel cold?

Yes. Anxiety and stress release adrenaline, which narrows blood vessels in the skin and makes the hands and feet cold and clammy. It can also trigger Raynaud's attacks. This usually passes as the anxiety settles.

Is feeling cold a sign of diabetes?

Not usually by itself. But diabetes can damage nerves and blood vessels, leading to cold, numb feet. Low blood sugar can cause sudden cold sweats and shakiness. Anyone with diabetes and cold, numb or discolored feet should have their feet checked.

Why do I feel cold after eating?

Feeling briefly cold after a large meal can happen as blood flow shifts to the gut. Feeling cold, sweaty and shaky a couple of hours after eating may be reactive low blood sugar. Feeling cold after eating very little is common with dieting.