Why Do I Get Hot And Cold At Night? | Causes And Relief

Waking up sweaty, then shivering under the same blanket, can feel confusing and a bit worrying. You toss off the covers because you are boiling, then pull them back on because you are freezing. Before you jump to worst-case ideas, it helps to know how your body, your bedroom, and your health all shape these swings.

This guide explains why the body flips between hot and cold at night, when it is likely harmless, when it points toward a health problem, and what you can do to sleep more comfortably. It does not replace care from your doctor or nurse, but it gives you solid background for a better conversation with them.

Getting Hot And Cold At Night: Normal Body Patterns

Your body does not keep a flat temperature around the clock. Core temperature usually falls in the evening, stays lower during the first half of the night, then rises toward morning as you move closer to waking. That change follows your internal clock and links to how sleepy or alert you feel.

During sleep, your brain adjusts blood flow to the skin and starts or stops sweating and shivering to balance heat. If the room is warm, bedding is thick, or sleepwear does not breathe well, you may overheat and sweat. When sweat evaporates, or if a fan blows across damp skin, you cool down fast and may wake up feeling chilled.

Many people type “why do i get hot and cold at night?” into a search box once they notice these swings more than once or twice a week. Sometimes this pattern is just a mix of normal temperature control and bedroom choices. Other times, hormones or medical issues play a part.

Possible Cause	What It Often Feels Like	Common Extra Clues
Normal Sleep Temperature Cycle	Warm at bedtime, cooler in the early hours, mild shivers when you wake briefly	Happens most nights in a similar way, no other symptoms
Room Too Warm	Overheating during the night with sweating, then feeling cold as sweat dries	Thermostat set high, closed windows, heavy comforter or many layers
Bedding Or Sleepwear	Hot under a thick duvet, cold once the covers are kicked off	Synthetic fabrics, plastic mattress protectors, foam mattress that holds heat
Hormone Shifts	Sudden waves of heat, flushing, then chills	Perimenopause, menopause, menstrual cycle changes, pregnancy
Infections And Fever	Hot, sweaty spells followed by chills and shaking	Fever, cough, sore throat, stomach upset, feeling unwell in the daytime
Thyroid Or Blood Sugar Problems	Episodes of sweating or feeling cold without obvious room changes	Weight change, tremor, fast heartbeat, diabetes or thyroid history
Sleep Apnea	Waking sweaty or chilled with sudden gasps or snorts	Loud snoring, pauses in breathing, morning headaches, daytime sleepiness
Medicines, Alcohol, Or Drugs	Fluctuations in temperature on nights when you take certain tablets or drink	New antidepressant, hormone treatment, pain medicine, or heavy evening drinking
Less Common Serious Illness	Drenching sweats that soak sleepwear, then chills	Weight loss, swollen glands, lasting cough, long-running fever

If your pattern lines up with the first few rows and you feel well in the daytime, simple changes to room temperature and bedding often help. If your pattern fits the last few rows or you feel unwell in general, your body may be flagging a deeper issue that needs attention.

Why Do I Get Hot And Cold At Night? Common Causes

When someone asks “why do i get hot and cold at night?” the answer usually falls into three broad groups: normal sleep control, hormone shifts, and medical conditions such as infection, endocrine problems, or medication effects. Several of these can overlap in the same person.

Hormones, Age, And Night Temperature Swings

Estrogen, progesterone, and testosterone influence how the brain regulates heat. During perimenopause and menopause, dropping and fluctuating estrogen can trigger hot flushes and night sweats, sometimes with chills once the sweat dries. Many women notice these spells years before their final period.

Menstrual cycle shifts, pregnancy, and breastfeeding can bring similar night sweating patterns. Some nights feel like a blast of heat, then a cool crash once the body attempts to shed that heat. This can come and go as hormone levels change across months or trimesters.

In men, lower testosterone in middle age, thyroid gland disorders, or treatment with hormone-blocking medicines for cancer can all prompt sweats and chills at night. These episodes often pair with low mood, fatigue, or changes in muscle mass.

Infections And Immune Response

When you fight an infection, your immune system may reset your internal “thermostat.” You shiver while temperature rises, then sweat once the fever breaks. That swing between hot and cold helps the body, yet it can wake you and drench the sheets.

Viral illnesses like flu or COVID-19, bacterial infections such as tuberculosis or endocarditis, and some fungal infections are all linked with night sweats. Night sweats that go on for weeks, especially with weight loss, ongoing fever, or a cough, call for a medical check to rule out conditions such as HIV or certain cancers like lymphoma.

Metabolism, Thyroid, And Blood Sugar

The thyroid controls how fast cells burn energy. An overactive thyroid can lead to feeling hot, sweating at night, weight loss, tremor, and a racing heartbeat. A sluggish thyroid often leads to cold intolerance, but some people describe mixed swings.

People with diabetes or other causes of low blood sugar may wake up sweaty, shaky, and chilled if their sugar level drops during sleep. Certain diabetes tablets are known to cause low sugar at night, which is one reason regular reviews with a clinician matter.

Medicines, Alcohol, And Other Triggers

Several common medicines list night sweats as a side effect. These include many antidepressants, some pain medicines, certain blood pressure drugs, and hormone treatments. Stopping some medicines suddenly can also unsettle temperature control.

Alcohol, nicotine withdrawal, and recreational drugs can all stir up sweating and chills at night. If your symptoms track closely with what you drink, smoke, or take, note the pattern and speak with the clinician who manages your care.

Bedroom Setup And Daily Habits That Make Nights Hot And Cold

Sometimes the cause sits less in the body and more in what happens around bedtime. A very warm room, heavy duvet, memory foam mattress, or thick pyjamas can trap heat. Once you overheat and start sweating, you cool sharply when that damp layer meets cooler air.

Late heavy meals, spicy food, caffeine, and alcohol close to bedtime raise metabolic rate or change blood flow to the skin. That can leave you flushed and sweaty right after you fall asleep, then chilly a few hours later when those effects fade. Simple tweaks here often bring quick relief.

Many sleep specialists advise aiming for a bedroom temperature around 18 °C (about 65 °F) and using breathable layers you can add or remove during the night. Thin cotton or moisture-wicking fabrics tend to feel more stable across the night than dense synthetics.

If you want an easy overview of common triggers, the NHS night sweats guidance lists frequent causes such as menopause, medicines, low blood sugar, and alcohol use, along with suggestions on when to see a doctor.

Practical Steps To Feel Less Hot And Cold At Night

You do not need to overhaul your whole life to test whether simple changes help. Start with a few small adjustments, then keep the ones that clearly improve your sleep.

Fine-Tune Your Room And Bedding

Set the thermostat a little lower than during the day and avoid strong heating right next to the bed. If you sleep with a partner, try separate blankets or a split-weight duvet so each person can pick a suitable level of warmth.

Swap thick flannel sheets or synthetic bedding for lighter cotton or linen. If you use a foam mattress or topper that holds heat, add a breathable cover between you and the foam. Choose sleepwear made from light natural fibres instead of polyester or fleece.

Adjust Evening Food, Drink, And Activity

Heavy meals, hot curries, caffeine, and alcohol in the hours before bed all raise the chance of flushing and sweating once you fall asleep. Try moving larger meals earlier in the evening and keeping late snacks small and bland.

Gentle exercise during the day helps overall sleep quality, but hard workouts right before bed can leave you hot and wired. Aim to finish vigorous activity a few hours before you plan to sleep.

Track Your Symptoms And Triggers

A simple symptom log can make patterns easier to see. On a notepad or app, jot down the time you went to bed, what you ate or drank late in the day, medicines taken, room temperature if you know it, and whether you woke hot, cold, or both.

When you later speak with a clinician, this log can help them link your night sweats and chills to hormones, medicines, lifestyle habits, or underlying illness. The Mayo Clinic list of night sweat causes gives a sense of how many different conditions can lie behind the same symptom.

Step	What To Try	Why It May Help
Cool The Room	Set bedroom to about 18 °C and keep air moving with a fan if needed	Reduces overheating so sweats are less likely to start
Layer Your Bedding	Use several light blankets instead of one heavy duvet	Makes it easier to adjust warmth without waking fully
Change Sleepwear	Switch to light, breathable fabrics and avoid thick socks or hats	Lets heat escape and reduces damp patches that lead to chills
Shift Meals And Drinks	Move large meals earlier and limit alcohol, caffeine, and spicy food at night	Prevents late spikes in metabolism that raise body heat
Review Medicines	Ask your regular doctor or pharmacist whether any tablet you take can trigger night sweats	Opens options to adjust dose or change to another drug if suitable
Use Cooling Aids	Place a cool pack near the feet, use breathable mattress toppers or moisture-wicking sheets	Targets hot spots and evens out temperature swings through the night
Keep A Symptom Log	Note dates, triggers, and how intense sweats and chills feel	Gives your clinician clear information for diagnosis and treatment planning

When Hot And Cold Nights Need A Medical Check

Short-lived or mild episodes that line up with a warm bedroom or a new duvet rarely signal serious disease. Still, some patterns deserve prompt medical attention.

Red-Flag Symptoms To Watch For

Speak with a doctor soon if any of the following apply:

• Drenching night sweats that soak sheets or sleepwear several times a week
• Unplanned weight loss over weeks or months
• Lasting fever, shivers, or general malaise
• A cough that does not settle, chest pain, or shortness of breath
• Swollen glands in the neck, armpits, or groin
• History of cancer, HIV, tuberculosis, or recent serious infection
• Night sweats plus severe thirst, passing urine often, or blackouts in someone with diabetes

If you wake sweaty and confused, have chest pain, struggle to breathe, or think you might be having a stroke or heart attack, treat that as an emergency and seek urgent care.

What A Clinician May Do

During a review, a clinician will ask about the pattern of your hot and cold spells, your medical history, and any medicine you take. They may examine your heart, lungs, lymph nodes, and thyroid. Blood tests can look for infection, hormone problems, or signs of cancer. Imaging or specialist referrals follow if needed.

Treatment depends on the cause. Hormone therapy, changes to antidepressants, treatment for sleep apnea, or medicine for infections can all reduce night sweats and chills once the right diagnosis is in place. Lifestyle changes around sleep, food, and alcohol then add an extra layer of relief.

Putting Night Temperature Changes In Perspective

Feeling hot and cold at night is common, and only a minority of people with this symptom turn out to have a serious disorder. Many find that a cooler bedroom, lighter bedding, and small shifts in evening habits already reduce sweats and chills.

Still, if you keep asking yourself “why do i get hot and cold at night?” after making these adjustments, or if you notice red-flag signs such as weight loss, lasting fever, or drenching sweats, listen to that concern and arrange a medical review. With a clear picture of your symptoms and solid information about possible causes, you and your clinician can work together toward calmer nights and steadier sleep.