Sweating or perspiration is the body’s way of cooling down. We can therefore expect sweating to be accompanied by heat, be it heat due to external factors like on a very hot day or heat generated within the body like with physical activity or a fever. When sweating occurs without a rise in body temperature, it is often referred to as cold sweat and can be a symptom of some very serious conditions.
What are cold sweats?
Cold sweats is a term used to describe perspiration without heat. In other words the surface of the body is not hot to touch and even an internal temperature reading with a thermometer does not indicate a higher than normal body temperature. Sweating unusually is also known as diaphoresis, which is a symptom of many diseases. Cold sweats are basically an abnormal reaction and should always be investigated.
Sudden cooling after being very hot and sweaty may also appear as cold sweats. For example, a person may exercise in a hot environment and then walk into a cold room which is air conditioned. The skin surface temperature suddenly drops while the sweat does not evaporate. As a result the skin may feel cold and clammy but this is a momentary change and should not be considered as a cold sweat.
Normal Sweating vs Cold Sweating
The body tries to maintain the internal temperature within a narrow range with 37ºC or 98.6ºF considered as the norm. It may fluctuate by about 0.5º either way and still be considered acceptable. When the body temperature is rising, the body has to cool down to prevent any disturbances to the system. This occurs with several different mechanisms, such as sweating.
Firstly the blood vessels on the skin surface dilate. This allows more blood flow to the surface with heat being lost from the blood, through the skin and into the environment. The skin will have a typically red or flushed appearance. Secondly the body stimulates the tiny sweat glands on the skin surface. This releases sweat which evaporates and in the process has a cooling effect. These are normal mechanisms.
With a cold sweat, the sweat glands are abnormally stimulated despite the lack of any excess heat. It is usually due to abnormal activation of the sympathetic nervous system. Nerve fibers running to the sweat glands triggers its activity and the glands then start producing and secreting more sweat, which is visible and palpable on the skin surface. It is often described as being cold and clammy.
Causes of Cold Sweats
There a diverse range of cause of cold sweats. Some are mild conditions and do not lead to any complications. Others can be very serious and even become life-threatening without prompt medical attention. The presence of other symptoms may be an indication of the possible cause. It is important that sudden and severe cold sweats are investigated as soon as possible to prevent serious complications.
Hot flashes is a common term to describe a sudden feeling of heat in the body. It is mainly experienced in menopause due to the hormonal changes that occur in women around this age. While it is not serious, it can be very uncomfortable and affect the quality of life. Sweating may also accompany the hot flashes. Sometimes excessive sweating occurs in menopause without any hot flash.
Hyperidrosis is the medical term for excessive sweating. It affects some people only in certain areas of the body while others may find it affects most parts of the body. Hyperhidrosis is believed to be due to an overactivity of the sympathetic nervous system which stimulates the sweat glands abnormally. Although not serious, it can be embarrassing and affect a person on a psychosocial level.
Hypoglycemia means low blood glucose levels. Cold sweats is one of the symptoms with hypoglycemia. The body usually maintains the blood glucose levels within a narrow range but once these levels drop below the normal lower limit, it can affect the body in various ways. Hypoglycemia is more likely to affect diabetics who do not control their diet or use the wrong dosage of blood-lowering drugs to control their diabetes.
A heart attack (myocardial infarction) is one of the more serious causes of cold sweats. A portion of the heart muscle (myocardium) dies due to blockage of the blood vessel (coronary artery) supplying it. Chest pain often with left arm and jaw pain, dizziness, confusions, nausea and shortness of breath are other symptoms that accompany the cold sweats. Immediate medical attention is necessary.
Hypotension (low blood pressure) can occur for a number of different reasons including heart failure and other heart conditions, endocrine diseases, severe allergic reactions and infections, blood loss, dehydration and poisoning. With mild hypotension, there may be little to no symptoms. Lightheadedness and dizziness are more common symptoms. It is usually with acute hypotension (sudden and severe) that symptoms like cold sweats arise.
Hypoxia means low oxygen levels in the body. This can arise with a number of different conditions including asphyxiation, poisoning, severe lung diseases and acute cardiac conditions. Cold sweats usually occurs with severe and sudden hypoxia. Dizziness, blurred vision and fainting may occur along with a very feint heartbeat and cold sweats. This is considered a medical emergency.
Shock is a broad term to describe conditions where the blood and oxygen supply to tissues within the body is insufficient. There are different types of shock which may arise due to a variety of causes. Cold clammy skin is one of the main symptoms of shock.. The different types of shock includes:
- Anaphylatic shock – severe allergic reaction.
- Cardiogeic shock – heart failure and other cardiac conditions.
- Hypovolemic shock – blood loss leading to low blood volume.
- Septic shock – severe infections like in septicemia (blood poisoning).
- Neurogenic shock – nervous system disruption or damage.
Shock is a medical emergency and can be life-threatening without prompt medical attention.
- Motion sickness
- Severe pain
- Vasovagal reaction
- Psychological stress
- Recurrent vomiting
- Infections like HIV and tuberculosis (TB)