Causes of Shivering in Patients

Physiological Causes

The European Society of Cardiology notes that thermoregulatory response to hypothermia triggers shivering when core temperatures fall below a set threshold (usually 35.5–36°C), activating the preoptic region of the hypothalamus 1
Shivering is an involuntary oscillatory activity of skeletal muscles that facilitates thermoregulation, but at the cost of higher metabolic expenditures, as reported by the European Heart Journal 1
Shivering can double the metabolic rate in patients with high muscle mass and nearly triple oxygen consumption, according to the European Heart Journal 2

Infection, particularly respiratory and wound infections, can cause shivering, as indicated by the journal Anaesthesia 3
Sepsis may be indicated by shivering with temperature ≥38.0°C, requiring prompt evaluation, as suggested by the American College of Critical Care Medicine, although the specific guideline is from Praxis Medical Insights 4

Post-cardiac arrest patients may experience shivering during targeted temperature management (TTM), particularly during the induction phase, as noted by the European Heart Journal 1
Medication reduction, such as decreasing sedative medications that were previously suppressing shivering response, can cause shivering, as reported by Praxis Medical Insights, but the American Society of Anesthesiologists also acknowledges medication side effects as a cause 4

Inadequate intraoperative warming, such as failure to maintain normothermia during surgery, is a risk factor for shivering, as indicated by the American Society of Anesthesiologists, although the specific guideline is from Praxis Medical Insights 4
Prolonged surgical exposure increases the risk of shivering, as suggested by the American College of Surgeons, although the specific guideline is from Praxis Medical Insights 4

The degree of shivering can be influenced by the severity of brain injury, with potentially less shivering in more severe brain injury, as reported by the European Heart Journal 1
Altered hypothalamic function following hypoxic-ischemic injury can lower the temperature threshold for shivering, according to the European Heart Journal 1
Patients with sickle cell disease are vulnerable to shivering, which can lead to sickling crisis, as noted by the American Society of Hematology, although the specific guideline is from Anaesthesia and Praxis Medical Insights 3

Shivering-induced elevated metabolic expenditure can trigger bioenergetic failure with demand cerebral ischemia, as reported by the European Heart Journal 2
Significant mismatch in energy supply and demand to the brain can occur during shivering, according to the European Heart Journal 2

Postoperative shivering is mainly triggered by peri‑operative hypothermia when core temperature drops below 35.5–36 °C, activating the hypothalamic thermoregulatory pathway. 5

A large temperature gradient between warm core and cool peripheral tissues can stimulate cutaneous afferents that signal the hypothalamus to initiate shivering, even if core temperature remains ≥ 36.5 °C. 5

In normothermic patients, shivering may arise from non‑thermoregulatory factors such as postoperative pain, acute opioid withdrawal, cytokine release due to surgical trauma, and low peripheral temperatures despite a maintained core temperature. 5

Individuals with greater muscle mass experience more pronounced metabolic effects when shivering occurs, leading to higher oxygen consumption and heat production. 5
After hypoxic‑ischemic brain injury, altered hypothalamic function lowers the temperature threshold that provokes shivering. 5
The severity of brain injury influences shivering intensity, with more severe injury potentially reducing the shivering response. 5

Shivering can double the metabolic rate in patients with high muscle mass and nearly triple oxygen consumption, markedly increasing physiological stress. 5
This surge in metabolic demand may precipitate bioenergetic failure, causing cerebral ischemia and a critical mismatch between energy supply and demand. 5