Cold sweats (diaphoresis) are episodes of sudden perspiration that occur without the typical triggers of high environmental temperature or physical exertion. This type of sweating is distinctly different from the body’s normal thermoregulatory process, which releases moisture to cool a person down when they are hot. Instead, cold sweats signal an internal physiological imbalance or a response to a physical or psychological stressor, often leaving the skin feeling clammy, cool, or cold to the touch.
The Physiology of Cold Sweats
The sensation of a cold sweat is rooted in the body’s “fight-or-flight” response, governed by the sympathetic nervous system. This branch of the autonomic nervous system prepares the body to face an immediate threat, whether real or perceived. When activated, the adrenal glands release a rush of stress hormones, primarily adrenaline and noradrenaline.
These hormones activate the eccrine sweat glands, which are the main producers of watery sweat across the skin’s surface. Simultaneously, the sympathetic nervous system initiates peripheral vasoconstriction, causing blood vessels close to the skin to narrow. This shunts warm blood flow away from the skin and towards the body’s core and vital organs, such as the heart, lungs, and brain. The diversion of warm blood flow causes an immediate drop in the temperature of the skin’s surface. The actively produced sweat then evaporates from this cooled, clammy skin, creating the characteristic “cold sweat” sensation.
Acute Triggers and Emotional Responses
The most common causes of cold sweats involve temporary states of psychological or physical distress. Intense emotional responses like acute stress, anxiety, or a panic attack immediately activate the sympathetic nervous system. The body reacts to the flood of stress hormones as if it were facing a physical danger, leading to a sudden onset of cold, clammy skin.
Extreme pain is another non-systemic trigger that can quickly induce this physical response. A sudden injury, a migraine, or the acute pain of a kidney stone causes the sympathetic nervous system to fire rapidly. This activation leads to the release of stress hormones and subsequent cold sweating. These acute episodes are typically self-limiting, meaning the cold sweats subside once the emotional or painful stimulus is removed or addressed. For instance, the cold sweat accompanying a panic attack will often resolve as the person calms down and the hormone levels normalize.
Systemic Medical Causes
Cold sweats can also be an indicator of a deeper physiological imbalance or a medical emergency requiring immediate attention. One frequent systemic cause is hypoglycemia, or dangerously low blood sugar, often defined as a blood glucose level below 70 mg/dL. When blood sugar drops too low, the body perceives it as a threat to brain function and triggers the release of adrenaline to raise glucose levels, resulting in cold sweats, shakiness, and confusion.
Conditions that cause the body to enter a state of shock are another trigger for cold sweats. Shock is a life-threatening condition where the body’s organs are not receiving adequate blood flow or oxygen, and it can stem from several causes. Hypovolemic shock, due to internal or external blood loss, causes the sympathetic system to constrict blood vessels to maintain core pressure, leading to profound cold sweats. Cardiogenic shock, resulting from the heart’s inability to pump enough blood, and septic shock, caused by a widespread infection, also initiate this response. In the case of infection, such as sepsis, cold sweats are a sign that the immune system is working intensely to fight the pathogen, often alongside a high fever or the body’s temperature rapidly fluctuating.
Furthermore, withdrawal from substances like alcohol or opioids can over-stimulate the nervous system, causing an outpouring of adrenaline that manifests as cold sweats and tremors. Hormonal shifts, such as those occurring during menopause or a thyroid disorder, can similarly disrupt the body’s temperature regulation, leading to unpredictable episodes of cold sweating.
When to Seek Medical Attention
While many cold sweat episodes are harmless and brief, certain accompanying symptoms act as “red flags” and necessitate immediate medical evaluation. Call emergency services if cold sweats occur alongside sudden chest pain, pressure, or discomfort that radiates to the neck, jaw, or arm. Seek urgent care if you experience difficulty breathing, shortness of breath, or a sudden, unexplained rapid heartbeat. Other concerning symptoms include:
- Confusion, lethargy, fainting, or a sudden change in mental status.
- Persistent abdominal pain or a weak pulse.
- Signs of circulatory distress, such as pale, ashen, or bluish lips and fingers.
If cold sweats are frequent, chronic, or occur without a clear, acute cause like stress or pain, it is important to schedule an appointment with a healthcare provider for a full assessment.