Causes of cold sweats and night sweats

The body normally produces sweat as a way to help keep cool. Sweating normally occurs with exertion such as when exercising or in high temperatures. However, there are other reasons for sweating.
Sweating can be triggered by fear or anxiety, and this is often referred to as a cold sweat. It comes on suddenly and results in cool, damp skin. It is the body's reaction to stress as part of the "fight or flight" response that helps us to react in a dangerous situation. A nightmare during sleep can trigger a cold sweat, and people with prolonged stress or anxiety problems can experience sweating as a symptom.

Cold sweat

A cold sweat is not a medical problem, but it can be a symptom of a serious condition that needs medical attention including:

• A serious injury that is causing pain
• Shock
• Heart attack
• Shortness of breath
• Too little sugar in the bloodstream

Excessive sweating can also be a symptom of many other disorders, whether a cold sweat or if it occurs during sleep as a night sweat. Doctors often hear their patients complain of night sweats. Night sweats refer to any excess sweating occurring during the night. However, if your bedroom is unusually hot or you are using too many bedclothes, you may begin to sweat during sleep - and this is normal. In order to distinguish night sweats that arise from medical causes from those that occur because one's surroundings are too warm, doctors generally refer to true night sweats as severe hot flushes occurring at night that can drench sleepwear and sheets, which are not related to an overheated environment.

In one study of 2,267 patients visiting a doctor, 41% reported experiencing night sweats during the previous month, so the perception of excessive sweating at night is fairly common. It is important to note that flushing (a warmth and redness of the face or trunk) may also be hard to distinguish from true night sweats.

Causes of excessive sweating

There are many different causes of excessive sweating. To determine what is causing excessive sweating in a particular individual, a doctor must obtain a detailed medical history and order tests to decide if an underlying medical condition is responsible for the sweating. Some of the known conditions that can cause excessive sweating are:

Menopause - The hot flushes that accompany the menopausal transition can occur at night or day and cause sweating. This is a very common cause of night sweats in women around the time of menopause.

Idiopathic hyperhidrosis - Idiopathic hyperhidrosis is a condition in which the body chronically produces too much sweat without any identifiable medical cause.

Infections - Classically, tuberculosis is the infection most commonly associated with night sweats. However, bacterial infections, such as endocarditis (inflammation of the heart valves), osteomyelitis (inflammation within the bones) and abscesses all may result in night sweats. Night sweats are also a symptom of HIV infection.