Being “cold natured” is an informal way of describing someone who feels cold more easily or more often than the people around them. It’s not a medical diagnosis. It refers to a personal tendency to reach for a sweater when everyone else is comfortable, or to dread air conditioning that others barely notice. While the phrase is casual, the experience is real and rooted in measurable differences in metabolism, body composition, blood flow, and even genetics.
Why Some People Run Colder Than Others
Your body generates heat primarily through metabolism, the constant process of converting food into energy. People with a higher basal metabolic rate produce more internal heat at rest, which means they can tolerate cool environments without much adjustment. People with a lower metabolic rate need to ramp up heat production more aggressively when temperatures drop, often shivering sooner and feeling uncomfortable faster.
Body composition plays a major role too. Muscle is the largest heat-producing tissue in most adults, and people with more muscle mass tend to maintain a stable core temperature during cold exposure more easily. Fat, on the other hand, acts as insulation. Its thermal conductivity is less than half that of other body tissues, so a layer of subcutaneous fat slows heat loss through the skin. People who are both lean and have lower muscle mass get hit from both sides: less heat generated and less insulation to keep it in.
There’s also a genetic component. Research has identified a mutation involving a protein called alpha-actinin-3. People who lack this protein can maintain a higher core temperature, conserve more energy, and shiver less during cold exposure compared to those with normal levels. This deficiency doesn’t cause any muscle disease. It simply shifts how the body handles cold.
Women Tend to Feel Colder
If you’ve noticed that women in your office are more likely to complain about the thermostat, there’s solid physiology behind it. Women generally have higher surface-area-to-volume ratios, lower muscle mass, and lower metabolic rates than men. One study found that standard indoor climate settings, based largely on male metabolic rates, may overestimate female metabolic rates by up to 35%. That’s a significant gap.
Blood flow patterns differ too. When hands are exposed to cold air between 8 and 14°C (roughly 46 to 57°F), skin blood flow in women during the early cooling phase is only about half that of men. Women also tend to constrict blood vessels in their extremities more aggressively, which protects the core but leaves fingers and toes noticeably colder. When that vasoconstriction isn’t enough, women typically begin shivering earlier than men to compensate.
Normal Body Temperature Is Lower Than You Think
The famous 98.6°F standard dates back to 1868 and no longer holds up. Researchers at Stanford Medicine found that average body temperature in the U.S. has dropped by about 0.05°F per decade since the 19th century, likely because of reduced chronic inflammation and better overall health. Today’s average hovers closer to 97.9°F, with a normal adult range of roughly 97.3 to 98.2°F.
This matters for cold-natured people because someone sitting at the lower end of that range, around 97.3°F, is starting from a cooler baseline than someone at 98.2°F. That difference is small but perceptible, especially in a chilly room. “Normal” body temperature is personal, and yours may simply run on the low side.
Medical Conditions That Cause Cold Sensitivity
Most cold-natured people are perfectly healthy. But persistent, worsening, or new-onset cold sensitivity can signal an underlying condition worth investigating.
Hypothyroidism
Thyroid hormones are central to how your body produces heat. They regulate your basal metabolic rate, stimulate energy-burning cycles in muscle tissue, and support the function of brown fat, a specialized tissue packed with mitochondria that converts energy directly into heat. When thyroid hormone levels drop, all of these systems slow down. The result is increased cold sensitivity, fatigue, and often unexplained weight gain. Even moderate hypothyroidism measurably reduces the body’s ability to generate heat in response to cold, and restoring thyroid hormone levels with treatment brings that capacity back.
Iron Deficiency Anemia
Iron is essential for making hemoglobin, the molecule in red blood cells that carries oxygen throughout your body. Without enough iron, your tissues don’t get the oxygen they need for efficient metabolism, and heat production drops. People with iron deficiency anemia often notice cold hands and feet, pale skin, and fatigue. Research has shown that iron-deficient individuals cannot maintain their body temperature during exposure to cool water (around 82°F) or cool air (around 61°F) compared to people with normal iron levels and similar body composition.
Raynaud’s Phenomenon
If your fingers or toes turn white or blue in response to cold and then flush red as they rewarm, you may have Raynaud’s phenomenon. This condition involves exaggerated spasms in the small blood vessels of the extremities, dramatically cutting blood flow in response to cold or stress. The primary form is common and mostly a nuisance. A secondary form can be associated with autoimmune conditions like lupus or scleroderma. Diagnosis typically involves examining the tiny blood vessels at the base of your fingernails under magnification and running blood tests for autoimmune markers.
Nutrients That Affect Heat Production
Beyond iron, several minerals play a direct role in your body’s ability to regulate temperature. Copper deficiency has been linked to lower body temperature and reduced circulating thyroid hormone levels. Zinc is required for energy and protein metabolism in nearly all cells, and depletion impairs the body’s cold response. Of these, iron deficiency is by far the most common in the general population, but chronic shortfalls in copper or zinc can also degrade thermoregulation.
If you’re consistently cold-natured and your diet is limited or you have absorption issues, nutritional gaps are worth considering. Foods rich in iron (red meat, lentils, spinach), zinc (shellfish, seeds, legumes), and copper (organ meats, nuts, whole grains) all support the metabolic machinery your body relies on to generate warmth.
Practical Ways to Stay Warmer
Layering clothing is the most immediate fix, but understanding why you’re cold opens up more targeted strategies. Building muscle mass through resistance training increases the amount of heat your body generates at rest. Staying well-nourished, particularly with adequate iron and other minerals, supports the metabolic processes behind thermogenesis. Staying hydrated matters too, since blood volume affects how efficiently your body distributes warmth to your extremities.
For cold hands and feet specifically, insulated gloves and warm socks help, but so does movement. Periodic activity keeps blood flowing to your extremities rather than pooling in your core. If your cold sensitivity is new, severe, or accompanied by other symptoms like fatigue, weight changes, or skin discoloration, a simple blood panel checking thyroid function, iron levels, and basic metabolic markers can rule out the most common medical causes.