Feeling hot and cold at the same time usually means your body’s temperature-regulation system is sending conflicting signals to different parts of you. Your core might be warming up while your skin cools down, or blood vessels in your extremities might be clamping shut (making your hands icy) while your torso flushes with heat. This mismatch is not a glitch so much as a feature of how thermoregulation works, but it can be amplified by fever, hormonal changes, thyroid problems, nerve damage, and a handful of other conditions that are worth understanding.
How the Thermostat in Your Brain Creates Mixed Signals
Your hypothalamus, a small region near the base of your brain, acts as a thermostat. It receives temperature data from sensors throughout your body and orchestrates responses to keep your core temperature within a narrow range. When it decides you need to warm up, it triggers shivering and constricts blood vessels near the skin to hold heat in your core. When it decides you need to cool down, it dilates those same blood vessels and triggers sweating. The sensation of being hot and cold simultaneously often happens because these two programs overlap or fire out of sequence. Your core may be running warm while your extremities have been cut off from warm blood flow, leaving your hands, feet, or nose cold to the touch even as your chest and face feel flushed.
This is especially pronounced during fever. When an infection resets your hypothalamic set point upward, your brain temporarily treats your normal body temperature as “too cold.” It responds by cranking up heat production through shivering and restricting blood flow to your skin. You feel freezing even though your actual temperature is climbing. Once the fever peaks, the set point drops back down, and suddenly your body is too warm. Sweating kicks in, blood rushes to the skin, and you feel overheated. The result is that strange oscillation between chills and hot flashes that anyone who has had the flu knows well. Fever as a response to infection is ancient, conserved across warm-blooded and cold-blooded vertebrates for hundreds of millions of years, which speaks to how fundamental and deeply wired this mechanism is.1PubMed Central. Fever and the thermal regulation of immunity: the immune system feels the heat
Fever Is Not the Only Reason for Chills
Many people assume that if they feel both hot and cold, they must have a fever. That is one possibility, but it is far from the only one. Severe infection can actually push the thermoregulatory system in the opposite direction. Research on sepsis shows that while mild infections tend to produce the classic fever response, severe systemic infection can cause a sustained drop in body temperature rather than a rise.2PubMed Central. Thermoregulation and survival during sepsis: insights from the cecal ligation and puncture experimental model In those cases, a person might feel hot internally because of widespread inflammation while their measured temperature is actually low. The disconnect between what the body is doing and what it feels like it is doing can be disorienting, and it is a reason to take mixed temperature sensations seriously if they come alongside signs of serious illness like confusion, rapid heartbeat, or extreme fatigue.
What Your Blood Vessels Are Doing Behind the Scenes
A big part of the hot-and-cold experience comes down to blood vessel behavior. When you are exposed to cold, whether it is the whole body or just your hands and feet, a strong vasoconstriction response kicks in. Blood vessels near the skin’s surface narrow rapidly, reducing blood flow to your extremities and dropping the temperature of your hands and feet. This impairs your sense of touch, reduces dexterity, and can be genuinely painful.3PubMed Central. Responses of the hands and feet to cold exposure
But the body does not just leave your fingers to freeze. After this initial clamping down, something called cold-induced vasodilation often kicks in, particularly in the fingers, toes, and face. Blood vessels briefly open back up, flooding those areas with warm blood, then clamp shut again. This cycle repeats, and it is sometimes called the “hunting response” because the body appears to be hunting for the right balance between protecting your core temperature and preventing frostbite in your extremities.3PubMed Central. Responses of the hands and feet to cold exposure If you have ever noticed your fingers alternating between numb-cold and tingling-warm during winter, that is exactly this cycle in action. The result, for the person living in that body, is the unsettling feeling of being both hot and cold at the same time in different regions.
Hormonal Changes and Temperature Chaos
Hormonal shifts are one of the most common reasons people experience simultaneous heat and cold sensations, and menopause is the classic example. Hot flashes during menopause are driven by declining estrogen levels, which disrupt the hypothalamus’s normal thermoregulatory feedback loop. Estrogen deficiency essentially uncouples the negative feedback system in the brain’s preoptic area, causing an exaggerated vasodilatory response to even a tiny increase in core body temperature.4Romanian Medical Journal. Hot flashes: Why? A small uptick that your body would normally handle quietly instead triggers a surge of blood to the skin, drenching you in heat and sweat. But the overcorrection often leaves you chilled moments later as your body cools down too aggressively.
The neurotransmitter norepinephrine plays a central role here. Agents that decrease norepinephrine release in the brain tend to reduce hot flashes, while things that increase it can trigger them.5Mayo Clinic Proceedings. Pathophysiology and Treatment of Hot Flashes This is why certain antidepressants that affect norepinephrine signaling are sometimes prescribed off-label for hot flashes, and it is also why stress, caffeine, and alcohol can all make the hot-cold cycling worse. Menopause is the most talked-about hormonal cause, but similar mechanisms show up in people undergoing androgen deprivation therapy for prostate cancer, in some thyroid conditions, and occasionally in younger people with hormonal irregularities.
When Your Thyroid Is Involved
Thyroid hormones have a direct and powerful effect on how much heat your body generates. They modulate thermogenesis through several routes: they change how active your brown fat cells are, they influence the metabolic rate of your skeletal muscles, and they interact with the sympathetic nervous system’s control of heat production.6Journal of Molecular Endocrinology. Effects of thyroid hormones on thermogenesis and energy partitioning When thyroid hormone levels are too low (hypothyroidism), your ability to generate heat in response to cold drops significantly. Research has shown that treating hypothyroidism roughly doubles cold-induced thermogenesis, meaning your body’s ability to warm itself in cool environments is cut in half when your thyroid is underactive.7PubMed Central. Resolution of Hypothyroidism Restores Cold-Induced Thermogenesis in Humans
People with hypothyroidism often describe feeling cold in their extremities and core while simultaneously experiencing episodes of flushing or sweating, particularly if their thyroid levels fluctuate or if they are being treated with replacement hormones that have not yet been properly dosed. Hyperthyroidism (an overactive thyroid) creates the mirror image: excessive heat generation, sweating, and heat intolerance, with occasional chills as the body overcorrects. Either direction of thyroid dysfunction can create that unsettling sense that your internal thermostat is broken.
Autonomic Dysfunction and Temperature Regulation
The autonomic nervous system manages all the unconscious processes behind temperature regulation: sweating, blood vessel dilation and constriction, heart rate adjustments, and more. When the autonomic system malfunctions, temperature control often goes haywire. Conditions like postural orthostatic tachycardia syndrome (POTS), which predominantly affects younger women, can produce a range of thermoregulatory symptoms. People with POTS frequently report feeling flushed and overheated in some body regions while simultaneously feeling cold and clammy in others, particularly in their hands and feet.
Autonomic dysfunction can occur as a standalone condition or as part of broader disorders, including diabetes, autoimmune diseases, and some post-viral syndromes. In long COVID, for instance, many people report new-onset temperature dysregulation with exactly this pattern of simultaneous hot and cold sensations. The underlying problem is usually that the blood vessels and sweat glands are not responding to signals from the brain in a coordinated way, so different body regions end up in contradictory thermoregulatory states.
Nerve Damage and Phantom Temperature Sensations
Small-fiber neuropathy is an underappreciated cause of confusing temperature sensations. The small nerve fibers in your skin are the ones responsible for detecting temperature and pain, and when they are damaged, they can send garbled signals to the brain. Symptoms typically include burning pain, shooting sensations, and abnormal sensitivity to touch, but they can also manifest as a persistent feeling that part of your body is hot, cold, or cycling between the two when the actual skin temperature is normal.8PubMed Central. Diagnosis and treatment of pain in small-fiber neuropathy
Small-fiber neuropathy can be caused by diabetes, autoimmune conditions, vitamin deficiencies (particularly B12), celiac disease, and certain infections. In some cases, no cause is found at all. What makes it tricky is that standard nerve conduction tests often come back normal because those tests measure large fibers, not the small ones responsible for temperature and pain. A skin biopsy looking at nerve fiber density in the outermost layer of skin is the most reliable way to confirm the diagnosis.8PubMed Central. Diagnosis and treatment of pain in small-fiber neuropathy If you have localized patches where you feel hot and cold at the same time, and those patches tend to be in your feet or lower legs, nerve damage is worth investigating.
Why It Happens at Night
Many people notice the hot-and-cold problem most acutely when they are trying to sleep. This is not coincidental. Your body actively drops its core temperature as part of the process of falling asleep. Warming the skin’s surface, especially on the hands and feet, promotes the onset of non-rapid-eye-movement sleep by triggering a circuit that connects skin temperature sensors to the hypothalamus, which then initiates body cooling.9Current Opinion in Physiology. Sleep and thermoregulation The result is that as you drift off, your skin is warm but your core is cooling, and that transition can feel like being hot and cold at the same time, especially if your room temperature, blankets, or pajamas are slightly off.
People going through menopause or those with thyroid issues tend to have this problem amplified at night because the hormonal disruptions discussed earlier collide with the natural circadian drop in body temperature. Night sweats followed by chills are one of the most commonly reported symptoms in perimenopause, and they directly reflect this collision between the body’s normal sleep-related cooling and a thermoregulatory system that has been destabilized by shifting hormone levels.
Exercise and the Paradox of Post-Workout Chills
If you have ever felt simultaneously overheated and shivery after a workout, you are not imagining it. During exercise, your core temperature rises and your body responds by dilating blood vessels near the skin to radiate heat. When you stop exercising, heat production drops quickly but the blood vessels stay dilated for a while, causing rapid skin cooling. Research on young women exercising in temperate room conditions found that cold sensations in the extremities increased significantly during rest periods before and after exercise at normal room temperature, while during exercise itself those cold sensations disappeared.10Physiological Reports. Body temperature and cold sensation during and following exercise under temperate room conditions in cold‐sensitive young trained females The study also found that some women were markedly more cold-sensitive than others in these post-exercise periods, suggesting a real physiological variation in how different people handle the transition from exercise to rest.
The practical takeaway: the post-workout window where your core is still warm but your skin has started to cool rapidly is a prime time to feel hot and cold at once. Layering up quickly after finishing exercise, rather than sitting in sweaty clothes, can make a noticeable difference.
Aging and Shrinking Thermoregulatory Margins
As people age, the body’s ability to regulate temperature narrows. Older adults tend to have lower baseline body temperatures than younger people, and their tolerance for both heat and cold becomes more limited. This happens because thermoregulation is not managed by a single organ but depends on the cardiovascular system, the respiratory system, metabolic rate, and more. As each of these systems declines with age, the overall capacity to respond to temperature challenges declines with them.11Gerontology. Age-Dependent Changes in Temperature Regulation – A Mini Review
For older adults, this means that the hot-and-cold sensation can show up in situations that would not bother a younger person. A mildly cool room might trigger vasoconstriction strong enough to make the hands uncomfortably cold while the core remains warm. Or a slight exertion might cause disproportionate sweating and flushing. The margins for comfortable thermoregulation simply get thinner with age, and mixed signals become more frequent as a result. This is compounded by the fact that many medications commonly prescribed to older adults, including beta-blockers, calcium channel blockers, and certain psychiatric medications, can directly interfere with the blood vessel and sweating responses that regulate temperature.
Medications That Mess With Your Thermostat
A surprising number of common medications can trigger or worsen the sensation of being hot and cold simultaneously. Beta-blockers reduce the heart’s ability to increase output in response to cold stress, which can leave you feeling chilled while your core temperature is fine. Some antidepressants, particularly SSRIs and SNRIs, affect serotonin and norepinephrine signaling in the hypothalamus and can trigger flushing, sweating, and subsequent chills. Opioids can blunt the fever response while causing sweating, and opioid withdrawal is notorious for producing intense alternating waves of heat and cold. Certain chemotherapy drugs and hormonal therapies (like tamoxifen or aromatase inhibitors) directly disrupt estrogen signaling and produce hot flashes similar to those seen in menopause.
If you started noticing the hot-and-cold pattern after beginning a new medication, that is worth mentioning to your doctor. It does not necessarily mean you need to stop the medication, but dose adjustments or timing changes can sometimes help. Medications that increase central norepinephrine activity tend to worsen hot flashes, while those that decrease it tend to help, which is consistent with the neurochemical model of thermoregulatory disruption.5Mayo Clinic Proceedings. Pathophysiology and Treatment of Hot Flashes
When Mixed Temperature Sensations Warrant Medical Attention
Most of the time, feeling hot and cold simultaneously is uncomfortable but not dangerous. It can reflect something as benign as a poorly ventilated room, a post-workout cooldown, or a mild viral illness running its course. But certain patterns are worth investigating. Persistent mixed temperature sensations that happen daily, especially if accompanied by unexplained weight changes, fatigue, or heart rate irregularities, could point to thyroid dysfunction or autonomic problems. Localized hot-cold sensations in the feet or hands that come with burning or shooting pain suggest possible small-fiber neuropathy. New-onset hot flashes in someone who is not in the expected age range for menopause deserve a hormonal workup. And the combination of feeling hot and cold with confusion, rapid pulse, or very low measured body temperature can indicate serious infection that needs urgent care.
A simple starting point is to actually measure your temperature when you feel the hot-cold mismatch. If your thermometer reads normal but you feel off, the problem is more likely vascular, hormonal, or neurological. If your temperature is genuinely elevated, an infectious or inflammatory cause moves up the list. That single data point can help both you and a clinician narrow down what is going on considerably.
Why Some People Run Hotter or Colder Than Others
Individual variation in baseline thermoregulation is real and often underappreciated. Body composition matters: people with more subcutaneous fat have better insulation but may overheat more easily during exercise. People with less fat lose heat faster and often report colder extremities. Metabolic rate varies substantially between individuals, and thyroid function sits at the center of that variation. Even fitness level plays a role. Well-trained individuals tend to start sweating sooner during exertion, which is a more efficient cooling response but can feel like overheating to the person experiencing it.
Sex differences are well-documented too. Women tend to have lower skin temperatures in their extremities than men, partly because of differences in body composition and partly because of hormonal influences on blood vessel tone. The research on cold-sensitive young women exercising in temperate conditions confirmed that some women experienced significantly greater cold sensations in their hands and feet during rest than others did under identical conditions.10Physiological Reports. Body temperature and cold sensation during and following exercise under temperate room conditions in cold‐sensitive young trained females If you have always been the person who needs a sweater when everyone else is comfortable, that is not just psychological. Your thermoregulatory setpoints and vascular responses are genuinely different, and those differences can make you more susceptible to the simultaneous hot-and-cold experience in everyday situations.