Feeling cold when others around you seem comfortable usually signals that your body is producing less heat, losing heat faster, or directing blood flow away from your skin and extremities. The causes range from simple explanations like low body weight or poor sleep to medical conditions like thyroid problems and anemia. Understanding what drives your internal thermostat can help you figure out whether your cold sensitivity is a quirk of your biology or something worth investigating.
Your Body Temperature Is Lower Than You Think
The old standard of 98.6°F as “normal” body temperature dates back to a German physician’s measurements in 1868. Research from Stanford Medicine shows that average body temperature in the U.S. has dropped by about 0.05°F every decade since then, likely because of reduced inflammation and improved living conditions. Today’s normal hovers closer to 97.9°F, with healthy adults falling anywhere between 97.3°F and 98.2°F.
This means your baseline might naturally sit on the lower end of that range. If your resting temperature tends toward 97.3°F, you’ll feel chilly in environments that are perfectly comfortable for someone running at 98.2°F. That difference alone can explain why you always seem to be the one reaching for a sweater.
Low Thyroid Function
Your thyroid gland acts as the body’s metabolic furnace. Thyroid hormones directly control your basal metabolic rate, which is the amount of energy your body burns at rest just to keep you alive and warm. When thyroid hormone levels drop (a condition called hypothyroidism), your metabolism slows and your body generates less heat.
Cold intolerance is one of the hallmark symptoms of an underactive thyroid. Other signs include fatigue, unexplained weight gain, dry skin, and feeling sluggish. Hypothyroidism is common, affecting roughly 5% of the population, and it’s easily detected with a blood test. If you’re persistently cold and also noticing these other symptoms, thyroid function is one of the first things worth checking.
Iron Deficiency and Anemia
Iron is the mineral your body uses to build hemoglobin, the protein in red blood cells that carries oxygen to your tissues. When iron levels are low, hemoglobin drops and oxygen delivery suffers. Poor oxygen circulation means less fuel for generating heat, and the result is often a constant feeling of being cold or experiencing frequent chills.
Iron deficiency is the most common nutritional deficiency worldwide, and it disproportionately affects women of childbearing age, vegetarians, and people with digestive conditions that impair absorption. Beyond cold sensitivity, signs include unusual fatigue, pale skin, brittle nails, and shortness of breath during mild activity.
Vitamin B12 deficiency produces a similar picture. B12 is essential for making red blood cells, so when levels are low, you can develop anemia just as you would with low iron. B12 deficiency also causes numbness or tingling in the hands and feet, which can overlap with or be mistaken for cold extremities. People over 50, those on plant-based diets, and anyone taking certain acid-reducing medications are at higher risk.
Low Body Weight and Body Composition
Body fat does two things that keep you warm: it insulates you against heat loss, and it reduces the rate at which heat escapes through your skin. Research on body composition and thermoregulation shows that people with higher body fat have lower conductive heat loss per unit of skin surface area, higher tissue insulation, and higher core temperatures. They also shiver less in cold environments compared to lean individuals.
If you have a low body mass index or a very low body fat percentage, you simply have less insulation between your core and the outside air. Your body also has to work harder to generate heat to compensate, which is why thin individuals often report feeling cold in rooms that others find comfortable. This is especially relevant for people who have recently lost significant weight or those with eating disorders.
Poor Circulation and Raynaud’s
When blood doesn’t flow efficiently to your hands and feet, those areas get cold fast. One of the more dramatic examples is Raynaud’s phenomenon, where blood vessels in the fingers and toes overreact to cold temperatures or stress. During an episode, affected fingers turn white or blue, go numb, and can sting or throb as blood flow returns.
Raynaud’s comes in two forms. Primary Raynaud’s has no underlying cause and is relatively harmless, though uncomfortable. Secondary Raynaud’s is linked to autoimmune or connective tissue diseases and tends to be more severe. Doctors can distinguish between the two by examining the tiny blood vessels at the base of your fingernails under magnification and running blood tests for autoimmune markers.
Common triggers include rapid temperature changes (like walking from a warm house into air conditioning), emotional stress, and smoking or vaping, all of which tighten blood vessels and reduce skin temperature.
Stress, Anxiety, and the Fight-or-Flight Response
When you’re stressed or anxious, your nervous system activates the fight-or-flight response. Part of that response involves narrowing blood vessels in your skin and extremities to redirect blood toward your vital organs and muscles. This is called vasoconstriction, and it’s why your hands and feet can turn ice-cold during a stressful meeting or an anxiety spike, even in a warm room.
If you live with chronic stress or an anxiety disorder, this response can fire frequently enough that cold hands and feet become your baseline. The fix isn’t always a blanket. Addressing the underlying anxiety through stress management, therapy, or lifestyle changes can improve circulation to your extremities.
Sleep Deprivation
The same neurons in your brain that regulate sleep also control your body temperature. When you don’t get enough rest, those systems go haywire. Research from Washington University found that sleep-deprived animals consistently sought out warmer environments, confirming what studies in humans have shown: losing sleep makes you feel colder.
This isn’t just about total sleep loss. Sleep fragmentation, being woken repeatedly throughout the night, produced the same shift toward cold sensitivity. If you’re chronically under-rested and always reaching for extra layers, improving your sleep quality may help more than turning up the thermostat.
Nerve Damage From Diabetes
Diabetic neuropathy, nerve damage caused by prolonged high blood sugar, can distort how you perceive temperature. Damaged nerves lose their ability to accurately sense cold and heat, which can make your feet feel persistently cold even when they’re objectively warm. High blood sugar also weakens the walls of tiny blood vessels that supply nerves with oxygen, compounding the problem.
Neuropathy can also disrupt how your sweat glands function, which interferes with your body’s ability to regulate temperature overall. If you have diabetes and notice cold feet paired with numbness, tingling, or a pins-and-needles sensation, neuropathy is a likely contributor.
Medications That Cause Cold Extremities
Certain blood pressure medications, particularly beta blockers, are well-known for causing cold hands and feet. These drugs work by blocking the effects of adrenaline on the heart, slowing it down and reducing blood pressure. But some beta blockers also block adrenaline’s effects on blood vessels throughout the body, which reduces blood flow to the extremities. This side effect is more pronounced in older adults.
If you started feeling persistently cold around the same time you began a new medication, it’s worth bringing up with your prescriber. Other drug classes, including some migraine medications and certain ADHD stimulants, can also affect circulation.
Sorting Out What’s Causing Your Cold Sensitivity
With so many potential causes, it helps to pay attention to the pattern. Cold that’s concentrated in your hands and feet points toward circulation issues, Raynaud’s, medication effects, or anxiety. A general, whole-body feeling of being cold suggests metabolic causes like thyroid problems, anemia, low body weight, or sleep deprivation. Cold sensitivity that developed suddenly or recently is more likely tied to a new medication, weight change, or emerging health condition.
A few straightforward blood tests can rule out or confirm the most common medical causes: thyroid function, iron levels, B12, and blood sugar. If those come back normal and you’re a healthy weight getting adequate sleep, your natural body temperature may simply run low, and layering up is a perfectly reasonable solution.