Why is my temperature high every night? Exploring potential causes

September 28, 2025 •

4 min read

The human body's core temperature naturally fluctuates throughout the day, often peaking in the evening. However, a consistently high temperature every night could signal an underlying issue. Discover the many factors that could be contributing to this frustrating and concerning nightly symptom.

Quick Summary

A persistently elevated temperature at night can stem from various sources, including hormonal shifts, environmental factors, underlying infections, or other medical conditions. The body's circadian rhythm naturally influences temperature, but persistent nighttime overheating warrants investigation to identify and address the root cause, which may range from minor issues to more serious health concerns.

Key Points

Circadian Rhythm: The body's core temperature naturally fluctuates, often peaking in the evening and dropping at night, but consistently feeling hot may indicate an issue.
Environmental Factors: Your sleep environment, including room temperature, bedding, and mattress type, can significantly impact how hot you feel at night.
Hormonal Shifts: Menopause, pregnancy, and thyroid issues can cause hot flashes and increased body temperature, especially during the night.
Infections and Inflammation: Persistent, unexplained fevers at night could be a sign of an underlying infection, autoimmune disease, or other inflammatory process.
Lifestyle and Habits: Eating heavy or spicy food, drinking alcohol or caffeine before bed, and exercising late can all affect your body's temperature regulation.
Medical Conditions and Medications: Underlying health problems or side effects from certain medications can cause night sweats or consistently high temperatures.
When to See a Doctor: If high nighttime temperatures are recurrent and accompanied by other symptoms like weight loss, it's important to seek professional medical advice for a proper diagnosis.

Understanding the body's natural thermostat

Your body's temperature regulation is a sophisticated process controlled by the hypothalamus, a small part of the brain that acts as your internal thermostat. This thermostat follows a circadian rhythm, or an approximately 24-hour cycle, causing your core temperature to naturally decrease in the evening as you prepare for sleep. In some cases, feeling hot at night might simply be a heightened perception of this natural process. However, when your temperature feels consistently high, it’s a sign that something is disrupting this rhythm or triggering an inflammatory response.

Environmental and lifestyle contributors

Sometimes, the explanation for a high nighttime temperature is relatively simple and tied to your immediate surroundings or daily habits. Optimizing these factors is often the first step in addressing the issue.

Sleep environment factors

Room temperature: Sleeping in a warm or humid room can interfere with your body's ability to cool down naturally.
Bedding and sleepwear: Heavy blankets and sleepwear made from non-breathable fabrics like fleece or down can trap body heat, leading to discomfort and overheating.
Mattress materials: Certain types of mattresses, particularly memory foam, can retain heat and contribute to a feeling of being hot all night.
Sleeping partners or pets: Sharing a bed with another person or a pet can significantly increase the overall temperature in the bed.

Diet and habits

Late-night meals and drinks: Consuming heavy, spicy, or protein-rich meals close to bedtime can raise your body temperature. The same is true for caffeine and alcohol, which can affect your body's temperature regulation and disrupt sleep.
Pre-sleep exercise: Engaging in intense physical activity too close to bedtime can elevate your core temperature and make it difficult to cool down before sleep.

Hormonal and physiological fluctuations

For many, hormonal shifts are a primary driver of nighttime overheating, especially in women. These changes can directly impact the body's thermostat.

Menopause and perimenopause

Hot flashes and night sweats are common symptoms during this period due to fluctuating estrogen levels. These can cause a sudden, intense feeling of heat that disrupts sleep.

Pregnancy

The hormonal changes and increased blood flow that occur during pregnancy can lead to a rise in core body temperature, making pregnant individuals feel warmer than usual at night.

Hyperthyroidism

An overactive thyroid gland produces excess thyroid hormone, which speeds up the body's metabolism. This can lead to heat intolerance, excessive sweating, and a persistently higher body temperature.

Stress and anxiety

The fight-or-flight response triggered by stress releases hormones like cortisol, which can increase heart rate, blood pressure, and body temperature. This can make it difficult to relax and sleep.

Medical conditions and medications

If environmental and hormonal factors are not the cause, a high nighttime temperature could be related to an underlying medical condition or medication side effect. Consulting a healthcare provider is essential in these cases.

Infectious diseases

Recurring fever: Consistent, low-grade fevers at night could indicate an underlying, ongoing infection that the body is fighting. Infections can range from minor to more serious conditions.
Fever of unknown origin (FUO): If a fever is present for an extended period without an apparent cause, a doctor may investigate potential infections, autoimmune diseases, or other conditions.

Autoimmune diseases

Conditions where the body’s immune system attacks its own tissues can cause inflammation and recurrent fevers. Examples include lupus, rheumatoid arthritis, and inflammatory bowel disease.

Neurological conditions

In some cases, damaged nerves can cause issues with temperature regulation, leading to heat intolerance and excessive sweating.

Medications

Certain medications can cause flushing, sweating, or affect temperature regulation as a side effect. Common culprits include some antidepressants, hormone therapies, and medications used to treat migraines.

Seeking a diagnosis

If you consistently experience a high temperature at night, especially when accompanied by other symptoms like weight loss, pain, or fever, it is important to speak with a healthcare professional. Your doctor will likely ask about your sleep habits, lifestyle, and other symptoms to help narrow down the cause. They may recommend diagnostic tests to rule out or identify underlying medical issues.

Comparing causes of high nighttime temperature


Cause	Description	Key Indicators	Management Strategies
Environmental	External factors like room temperature, bedding, and sleepwear.	Feeling hot in bed, but cool in other rooms; discomfort lessens with adjustments.	Adjust thermostat, use breathable fabrics, stay hydrated, use a fan.
Hormonal	Fluctuations in hormones due to menopause, pregnancy, or thyroid issues.	Night sweats, hot flashes, heat intolerance, other hormonal symptoms.	Talk to a doctor about hormone therapy or medication adjustments.
Infections	Ongoing or low-grade infection causing the body to raise its temperature.	Recurrent fevers, chills, fatigue, body aches, other signs of illness.	Consult a doctor for diagnosis and appropriate treatment.
Stress/Anxiety	Psychological stress activating the fight-or-flight response.	Increased heart rate, difficulty relaxing, correlation with stressful events.	Stress management techniques, breathing exercises, therapy.
Medications	Side effects of specific drugs affecting temperature regulation.	Symptoms appear after starting a new medication.	Discuss potential alternatives or dosage changes with your doctor.

Conclusion

While a high nighttime temperature can be disruptive and worrying, it's often a symptom with a manageable cause. By first evaluating environmental and lifestyle factors, you can address the simplest possibilities. If the issue persists, seeking professional medical advice is crucial to rule out hormonal imbalances, underlying infections, or other health conditions. A thorough evaluation can lead to the right diagnosis and treatment, helping you return to more restful, comfortable nights. For more authoritative medical information, you can consult sources such as the National Institutes of Health.

Frequently Asked Questions

Yes, chronic stress and anxiety can activate the body’s fight-or-flight response, releasing hormones that increase heart rate and body temperature. This can disrupt sleep and cause you to feel overheated at night.

Heavy bedding, non-breathable sleepwear, and a warm room can trap body heat, preventing your core temperature from dropping naturally. Using lightweight, breathable fabrics and keeping your room cool can help manage this.

Not necessarily. Your body's temperature can feel elevated due to external factors like a warm room or heavy blankets. A true fever is a consistent elevation of your body's set-point temperature, usually defined as 100.4°F or higher.

Hormonal changes, such as those during menopause, pregnancy, or due to thyroid issues, can disrupt the body's natural thermoregulation. These shifts can trigger hot flashes and night sweats, leading to a feeling of being hot.

If you experience recurring fevers, night sweats, or feel hot consistently at night, especially when accompanied by other unexplained symptoms like weight loss, it is best to consult a healthcare provider to rule out underlying medical conditions.

Yes. Consuming spicy food, caffeine, or alcohol before bed can increase your metabolic rate and affect blood vessels, both of which can lead to a higher body temperature and disturbed sleep.

Yes, some medications have side effects that can include flushing or night sweats. If you've recently started a new medication and notice a change in your nighttime temperature, discuss it with your doctor.

A doctor can order tests to check for signs of infection or inflammation. Keeping a log of when you feel hot and any other symptoms can help your doctor in the diagnostic process.

Night sweats are episodes of excessive sweating at night that can drench clothing or bedding and are often associated with hormonal shifts or infections. Simply feeling hot might not involve excessive sweating and could be caused by environmental factors.