Night sweats

ALSO KNOWN AS: Sleep hyperhidrosis

RELATED CONDITIONS: Menopause, obstructive sleep apnea, infection, low blood sugar, lymphomas and other cancers, certain medications

DEFINITION: Night sweats are excessive nighttime sweating that causes the individual to wake up and may require the individual to bathe or change nightclothes.

Risk factors: There are some diseases and conditions that may be associated with an increased incidence of night sweats. Individuals who have obstructive sleep apnea, a disorder in which breathing is interrupted during sleep, are more likely to experience night sweats. Risk factors for sleep apnea, such as obesity, therefore may also be risk factors for night sweats. Women experiencing menopause are also more likely to experience night sweats.

Etiology and the disease process: Night sweats can be caused by a number of underlying diseases and conditions, as well as by a simple excess of bedding or an overly warm room. Some of the most common medical causes of night sweats include the changing hormone balance that occurs during menopause, obstructive sleep apnea, infection, low blood sugar (hypoglycemia), cancer (especially lymphoma), and certain medications. Other causes can include infection with the human immunodeficiency virus (HIV), tuberculosis, hyperthyroidism, epilepsy, and head injury.

Incidence: There are few significant scientific studies focusing exclusively on the incidence of night sweats; however, they are believed to be very common. One study of night sweats found that 41 percent of the 2,267 patients who were studied reported night sweats. A systematic review found between 10 and 41 percent of primary care patients experienced night sweats. Many physicians report a significant percentage of individuals they see in their general practice complain of night sweats.

Symptoms: The symptoms of night sweats are waking up at night because of excessive sweating. Night sweats are considered mild if they wake sleepers, who then remove some or all bed coverings and may turn over the pillow to use the dry side. Night sweats that make sleepers feel the need to wash the sweat off their hands or faces are considered moderate. Night sweats are considered severe when the sweating is so excessive as to cause sleepers to change their clothes or take a shower. Some people who experience night sweats also experience excessive sweating during the day.

Screening and diagnosis: The physician will typically take a history of the patient’s night sweat experiences and perform a physical exam to see if any common causes of night sweats seem to be a likely cause. The physician may also ask a series of questions, which may involve travel history, to determine if the patient has been in any areas that increase the likelihood of becoming infected with a disease such as tuberculosis or if there is a risk of infection with HIV. The doctor may also ask the patient’s sleeping partner about symptoms of which the individual may be unaware, such as the loud snoring that often accompanies obstructive sleep apnea.

If these steps fail to determine why the night sweats are occurring, the doctor may order blood tests or additional screening procedures to test for other causes. The doctor will also ask the patient about other unusual symptoms, even those that do not seem to be related. Many diseases and conditions that can cause night sweats usually cause other symptoms as well. Types of cancer that cause night sweats are usually associated with unintentional weight loss and fever. Tuberculosis is also usually accompanied by weight loss, a cough, and a low-grade fever.

Treatment and therapy: Most night sweats are treated by assessing the underlying cause and treating that disease or condition, including a possible lymphoma. Resolving the underlying problem will usually eliminate the night sweats. However, while the underlying problem is being diagnosed and treated, or if no treatable underlying cause can be found, some techniques may help relieve the symptoms.

Reducing the quantity of bedclothes or switching from heavy blankets made of insulating materials such as wool to lighter blankets made of fabrics such as cotton may help reduce the occurrence of night sweats or reduce their severity. Sleeping with a window open or a fan pointed toward the bed may also help to relieve the problem. Avoiding spicy food, excessive exercise before bedtime, alcohol, and tobacco may help to reduce the severity of night sweats.

Some medications may help alleviate or lessen the severity of night sweats. Hormone replacement therapy can help menopausal women, antidepressants and gabapentin alleviate some night sweats symptoms, and clonidine can reduce blood pressure and alleviate night sweats. 

Prognosis, prevention, and outcomes: Sleeping in a cool room without an excess of bedding may be able to help prevent some episodes of night sweats. The prognosis for most cases of night sweats is good. Treating the underlying cause, if one can be found, is usually effective at eliminating the night sweats. Night sweats can be extremely frustrating as they can lead to poor quality of sleep and increased drowsiness during the day. Treating night sweats successfully can lead to a better quality of sleep, as well as an increased quantity of sleep, which can improve mood and lead to a better overall.

Bibliography

Freedman, Jeri. Lymphoma: Current and Emerging Trends in Detection and Treatment. New York: Rosen, 2006.

Mold, James W., Barbara J. Holtzclaw, and Laine McCarthy. "Night Sweats: A Systematic Review of the Literature." Journal of the American Board of Family Medicine, vol. 25.6, 2012, pp. 878–93.

Mold, James W et al. “Prevalence of Night Sweats in Primary Care Patients: An OKPRN and TAFP-Net Collaborative Study.” The Journal of Family Practice, vol. 51.5, 2002, pp. 452-6.

Tobias, Jeffrey, and David Hochhauser. Cancer and Its Management. 6th ed. Hoboken: Wiley-Blackwell, 2010.

“What Are Hot Flashes and Sweating?” American Cancer Society, 9 Dec. 2020, www.cancer.org/cancer/managing-cancer/side-effects/hair-skin-nails/hot-flashes-sweating/what-are-hot-flashes-and-sweating.html. Accessed 14 June 2024.

“What Causes Night Sweats?” Sleep Foundation, 1 Feb. 2024, www.sleepfoundation.org/night-sweats/causes-of-night-sweats. Accessed 14 June 2024.

Yarbro, Connie Henke, Debra Wujcik, and Barbara Holmes Gobel, eds. Cancer Symptom Management. 14th ed. Burlington: Jones, 2013.