Symptoms
Night sweats: causes and when to worry
Is this an emergency?
This is not an emergency service. Call 911 or go to the nearest emergency room if you have:
- Sweating with chest pain or pressure, or shortness of breath
- A very fast heartbeat with dizziness or fainting
- Cold sweats with shaking and confusion, especially if you have diabetes
- High fever with confusion or a stiff neck
Help lines
Night sweats are bouts of heavy sweating during sleep that can soak your clothes or sheets. They often come from heat, menopause, alcohol or a medicine. But if they last more than 2 weeks and come with fever, unexplained weight loss or swollen lymph nodes, you need a prompt in-person evaluation. By video, the doctor evaluates you and gives you a lab order.
Other names: Nighttime sweating, Nocturnal sweating
Possible causes
A hot room or heavy bedding
Very common in Puerto Rico’s climate; improves when the room is cooler
Menopause and perimenopause
Hot flashes at night, changing periods, after 40
Infections with fever
Sweating as the fever breaks
Medicines
Thyroid hormone, fever reducers and some antidepressants
Low blood sugar at night
With insulin or other diabetes medicines; cold sweat, shaking
Hyperthyroidism
Feeling hot and sweating with a racing heart, nerves and weight loss
Tuberculosis
Cough for 3 weeks or more, fever and weight loss: in-person evaluation
Lymphoma
Drenching sweats with fever, weight loss or swollen nodes: prompt in-person evaluation
On this page(6)
First: when night sweats need an in-person evaluation
Get an in-person evaluation soon if sweats soak you night after night for more than 2 weeks and you also have unexplained fever, unexplained weight loss, swollen lymph nodes, or a cough lasting 3 weeks or more. According to the CDC, tuberculosis causes a long-lasting cough, fever, weight loss and sweating at night. According to the National Cancer Institute, fever with no known cause, drenching night sweats and unexplained weight loss are signs that are checked in lymphoma.
That doesn’t mean it is something serious, but it isn’t something to be reassured about by video: you need an exam and tests. The doctor, as your primary care doctor by video, can help you set up that evaluation, as described below.
Common causes of night sweats
The table on this page sums up the most common causes. According to MedlinePlus, extra sweating can come from:
- A hot room or heavy bedding, very common in Puerto Rico.
- Menopause and perimenopause: hot flashes at night. See menopause.
- Fever and infections, from the flu to longer-lasting infections.
- Medicines, such as thyroid hormone, fever reducers and some medicines for depression or other mental health conditions.
- Alcohol or caffeine, and withdrawal from alcohol or some medicines.
- Low blood sugar at night, especially if you use insulin or other diabetes medicines. See low blood sugar.
- Overactive thyroid: sweating and feeling hot with a racing heart and nervousness. See hyperthyroidism.
- Anxiety or stress.
- Less often, infections such as tuberculosis or HIV, or a cancer such as lymphoma.
How we help by video if you wake up sweating
You see Dr. Diana Nieves Castro, MD, a Puerto Rico–licensed general practice physician with several years of emergency-department experience, in English or Spanish. She asks how long it has been happening, how many nights, whether it soaks you, whether you have fever, cough, weight loss or swollen lymph nodes, how your periods are, which medicines you take and how much alcohol you drink.
We evaluate, diagnose and treat. If needed, we give you a lab order for a lab near you: for example a blood count, thyroid tests or, with your consent, an HIV test. If you need a TB test, we explain how to get one. If the cause is a medicine or menopause, the doctor explains your options and, if appropriate, prescribes and we send your prescription to your pharmacy. If you need a physical exam, an X-ray or other studies, we refer you.
A doctor visit costs US$79, the same price for every age. Request a visit online 24/7 — we confirm your time by email or text.
Your doctor
Dr. Diana Nieves Castro, MD
General practice physician
Several years of emergency-department experience.
Founding Executive Director of The Health Initiative.
What you can do at home
For sweats from heat or menopause, these steps help. MedlinePlus especially recommends drinking fluids and lowering the room temperature a little.
- Lower the room temperature a little, or use a fan.
- Use light sleepwear and sheets.
- Drink enough water to replace what you sweat.
- Avoid alcohol and caffeine, especially at night.
- Write down how many nights it happens and whether you have a fever, to tell the doctor.
When to go to the ER
MedlinePlus advises getting checked if sweating comes with chest pain, fever, a racing heartbeat, shortness of breath or weight loss. For your safety, go to the emergency room or call 911 if you have:
- Sweating with chest pain or pressure, or shortness of breath
- A very fast heartbeat with dizziness or fainting
- Cold sweats with shaking and confusion, especially if you have diabetes (very low blood sugar)
- High fever with confusion or a stiff neck
Frequently asked questions
Why do I wake up sweating?
Can night sweats be serious?
Which tests are done for night sweats?
Are night sweats a sign of menopause?
About this page
Author: The Health Initiative
Medical care provided by Dr. Diana Nieves Castro, MD (PR license 24027)
Disclosure: Founding Executive Director of The Health Initiative
Published: 2026-10-02 · Updated: 2026-10-02
Sources (5)
- Sweating (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- HIV (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- Hyperthyroidism (MedlinePlus, NIH) (opens in a new tab) (accessed 2026-10-02)
- CDC: Signs and Symptoms of Tuberculosis (opens in a new tab) (accessed 2026-10-02)
- Adult Hodgkin Lymphoma Treatment (PDQ), National Cancer Institute (opens in a new tab) (accessed 2026-10-02)