It starts as a shiver. You reach for the heavy wool blanket, tucking it tight around your chin because your teeth are practically chattering. Two minutes later, you’re kicking the covers off, drenched in a light sweat, and frantically searching for the fan remote. It’s an exhausting cycle. Being cold and hot at the same time is more than just a minor annoyance; it’s a signal that your body’s internal thermostat is flickering like a bad lightbulb.
Usually, our bodies are masters of homeostasis. The hypothalamus, a tiny almond-sized region in your brain, acts as the master commander. It keeps you at roughly 98.6°F. But when things go sideways, you end up in this weird thermal limbo.
The Fever Paradox: Why Chills and Heat Happen Together
When you have an infection, your body isn't just "getting hot." It’s actually raising its internal set point. Think of it like someone walking into your house and cranking the thermostat up to 103°F. Because your current body temp is still 99°F, you feel freezing. Your muscles shake—that's the shivering—to generate heat and reach that new, higher target.
Then the "break" happens.
Once your immune system starts winning or the Tylenol kicks in, the hypothalamus resets to normal. Suddenly, you’re at 102°F but your brain wants you at 98.6°F. You feel like you're standing in a furnace. You sweat. You flush. You wonder why am i cold and hot at the same time while your body desperately tries to dump the excess heat it just fought so hard to create. It’s a literal internal tug-of-war.
Hormones Are The Usual Suspects
If you aren't sick with a flu or a virus, your hormones are probably the culprits. This isn't just about menopause, though that’s the most famous example. Perimenopause can start in a woman's late 30s or 40s. Estrogen levels begin to fluctuate wildly. Estrogen has a direct line to the hypothalamus; when it drops, the brain mistakenly thinks the body is overheating.
The result?
💡 You might also like: Medicine Ball Set With Rack: What Your Home Gym Is Actually Missing
A hot flash. Your blood vessels dilate (vasodilation) to let heat out. But then, as the flash subsides, your skin is damp from sweat and your vessels constrict. Now you’re clammy and shivering. It’s a rollercoaster.
Men aren't exempt from hormonal thermal weirdness either. Low testosterone or "andropause" can cause similar night sweats and temperature sensitivity. Even thyroid issues—specifically hyperthyroidism or Hashimoto’s—can leave you feeling like you can't find a "middle ground." One minute your metabolism is racing and you're burning up; the next, you're sensitive to the slightest draft.
Anxiety and the Nervous System
Stress is a physical event. When you’re stuck in a high-cortisol loop or a panic attack, your "fight or flight" system (the sympathetic nervous system) takes the wheel. It redirects blood flow.
It pulls blood away from your skin and toward your vital organs and large muscles. Your hands and feet might get ice cold. Meanwhile, your core temperature rises because your heart is racing and your metabolism is revving up. You might feel a "hot flush" in your face while your fingers feel like popsicles.
Anxiety creates a fractured physical experience. You aren't imagining it. Your body is literally different temperatures in different places.
Medications That Mess With Your Thermostat
Sometimes the call is coming from inside the house—or rather, the medicine cabinet. A surprising number of drugs list "thermometabolic changes" as a side effect.
📖 Related: Trump Says Don't Take Tylenol: Why This Medical Advice Is Stirring Controversy
- SSRIs and SNRIs: Common antidepressants like Sertraline or Venlafaxine can increase sweating and alter how your brain perceives temperature.
- Stimulants: Everything from ADHD meds (like Adderall) to that third cup of espresso can constrict blood vessels and raise your core temp.
- Withdrawal: If you miss a dose of certain medications, your nervous system can go into a minor shock, leading to "brain zaps" and alternating chills/sweats.
Anemia and Iron Deficiency
Let's talk about blood. If you don't have enough healthy red blood cells to carry oxygen, your circulation suffers. People with iron-deficiency anemia often feel cold most of the time, especially in their extremities. However, because their system is struggling to function efficiently, any physical exertion can make them feel overheated and exhausted quickly. It’s a paradox of feeling fragile and "off-balance" thermally.
Simple Environmental Triggers
Honestly, sometimes it’s just physics. If you’re in a room with a space heater and a drafty window, your body is receiving conflicting data. Your skin sensors are sending "Too Hot" and "Too Cold" signals simultaneously.
Humidity plays a role too. High humidity prevents sweat from evaporating. If you can't evaporate sweat, you can't cool down. You stay hot and wet, but the moment a breeze hits that moisture, you get a localized chill.
When Should You Actually Worry?
Most of the time, feeling cold and hot at the same time is a temporary glitch. Maybe you're fighting a cold you don't know you have yet. Maybe you had too much caffeine. But there are times when it’s a red flag.
If these temperature swings are accompanied by unexplained weight loss, a visible lump in your neck (thyroid), extreme fatigue, or drenching night sweats that soak through your pajamas every night, it’s time for blood work. Doctors usually check your TSH levels (thyroid), a CBC (complete blood count) for anemia or infection, and your glucose levels. Diabetes can also cause neuropathy, which makes your limbs feel cold or "burning" regardless of the actual temperature.
Actionable Steps to Stabilize Your Temp
Stop fighting your environment and start managing your biology.
👉 See also: Why a boil in groin area female issues are more than just a pimple
Layering is a science. Don't just wear a heavy coat. Wear a moisture-wicking base layer (like merino wool or synthetic athletic gear) that pulls sweat away from your skin. If you stay dry, you won't get that "post-sweat chill."
Watch the "Thermal Spikes." Avoid large amounts of alcohol or spicy foods in the evening. Alcohol causes vasodilation—it makes you feel warm initially (the "beer blanket"), but then causes your body temperature to drop as you lose heat through your skin, leading to 3:00 AM shivers.
Hydration and Electrolytes. If you’re cycling between hot and cold, you’re losing fluids. Plain water isn't always enough. Make sure you're getting magnesium and potassium, which help the nervous system regulate those "shiver" triggers more effectively.
The Wet Sock Method. It sounds crazy. But some naturopaths suggest that if you're stuck in a feverish "cold/hot" loop, putting on cool, damp cotton socks covered by dry wool socks can actually stimulate circulation and help the body regulate its temperature more quickly.
Track the Pattern. Keep a simple log for three days. Note what you ate, your stress level, and when the temperature swings happened. If it’s always 20 minutes after a meal, it’s likely metabolic or blood sugar related. If it’s only at night, it’s likely hormonal or environmental.
Living in a state of thermal confusion is exhausting for your heart and your brain. Identifying whether the cause is a flickering thyroid, a hidden infection, or just a heavy-handed caffeine habit is the first step toward finally feeling comfortable in your own skin again. Check your temperature with a reliable thermometer during these episodes; if your actual temp is normal, the issue is likely your perception of heat, which points toward nerves or hormones rather than a physical fever.