Cold sweats, medically known as diaphoresis, are episodes of sudden, clammy sweating that occur independently of external temperature or physical exertion. Unlike the normal sweating mechanism that cools the body down, cold sweats are a symptom of the body’s involuntary “fight or flight” response. This reaction is triggered by the sympathetic nervous system releasing stress hormones, like adrenaline, which stimulate the sweat glands. The resulting moisture on the skin then causes a chill, making the person feel cold despite the sweating. Cold sweats are a nonspecific warning signal that the body is experiencing a significant internal disturbance, which can range from temporary stress to a medical emergency.
Immediate Physiological Stressors
The most rapid triggers for cold sweats are those that suddenly activate the body’s acute stress response. Severe, sudden pain from an injury, such as a broken bone, or an internal event like a kidney stone, causes a flood of adrenaline that activates the sweat glands. Acute emotional distress, such as a panic attack or extreme fear, functions similarly by initiating the fight-or-flight pathway, leading to diaphoresis. Another common physiological trigger is vasovagal syncope, or fainting, caused by a sudden, temporary drop in blood pressure. Before passing out, the body attempts to compensate for reduced blood flow to the brain, which often manifests as a cold sweat, lightheadedness, and pallor.
Underlying Systemic and Metabolic Conditions
Recurrent or ongoing internal imbalances frequently cause cold sweats by continuously disrupting normal bodily functions. Hypoglycemia, or low blood sugar, is a common metabolic cause. When this occurs, the brain, which relies heavily on glucose for fuel, signals the adrenal glands to release adrenaline and noradrenaline. This hormonal release is a rescue mechanism intended to stimulate the liver to release stored glucose, but it simultaneously causes the classic symptoms of clammy, cold sweating, shaking, and confusion.
Hormonal shifts also play a significant role, particularly in women experiencing perimenopause or menopause. These changes can lead to vasomotor symptoms, known as hot flashes, which involve a sudden sensation of heat followed by profuse sweating and subsequent chills. Conditions affecting the thyroid gland, such as hyperthyroidism, can accelerate metabolism, causing increased heat production and sweating that may present as cold sweats.
Chronic, generalized anxiety disorders can lead to persistent sympathetic nervous system overactivity, resulting in frequent, unexplained bouts of cold sweats. Systemic infections, like sepsis, or the process of a high fever breaking can also lead to cold sweats. As the body fights off pathogens, the core temperature rises, and when the fever finally breaks, the body rapidly cools itself through intense sweating, leaving the skin cold and clammy.
Medications and Substance Withdrawal
Certain pharmaceutical agents can cause cold sweats as a side effect by interfering with the body’s temperature regulation or nervous system. Selective serotonin reuptake inhibitors (SSRIs), a class of antidepressant, are known to cause diaphoresis because serotonin can influence the hypothalamus, the brain’s thermostat. Some opioid pain medications, such as oxycodone and morphine, can also trigger sweating, sometimes by stimulating mast cells to release histamine, leading to flushing and perspiration.
The cessation of certain substances can also induce cold sweats due to the resulting hyperactivity of the sympathetic nervous system. In alcohol withdrawal, the sudden absence of the depressant effect leads to a rebound over-excitation of the nervous system, causing tremors, anxiety, and excessive sweating. Similarly, during opioid withdrawal, the body experiences a complex physiological rebound, where altered enzyme activity leads to cycles of hot and cold flashes. The subsequent evaporation of sweat causes the sensation of being cold. This autonomic dysregulation is a common feature of withdrawal from both alcohol and opioids.
Recognizing When Cold Sweats Are a Medical Emergency
Cold sweats can be an early indicator of a life-threatening medical event, requiring immediate attention when accompanied by other serious symptoms. One concern is the possibility of shock, a condition where the body’s organs are not receiving enough blood or oxygen. Shock can be caused by severe blood loss, overwhelming infection (septic shock), or heart failure (cardiogenic shock).
If cold sweats are accompanied by chest pain, which may radiate to the arm or jaw, or by sudden, severe shortness of breath, a heart attack must be suspected. Other accompanying symptoms requiring immediate medical intervention include confusion, fainting, a weak or rapid pulse, and severe abdominal pain.