What are the possible causes and treatments for a patient experiencing episodes of hypothermia during sleep?

Extreme Cold Spells During Sleep: Causes and Management

If you are experiencing episodes of feeling extremely cold during sleep, the most likely causes are environmental factors, medication effects, or underlying medical conditions affecting thermoregulation—immediate assessment should focus on room temperature, bedding adequacy, medication review (especially antipsychotics, benzodiazepines, and beta-blockers), and screening for hypothyroidism, hypoglycemia, and autonomic dysfunction.

Immediate Assessment Priorities

Environmental and Behavioral Factors

• Check ambient temperature: Room temperature below 18-20°C (64-68°F) combined with inadequate bedding is the most common cause of nocturnal cold sensation 1
• Assess bedding and clothing: Wet or damp bedding from night sweats or enuresis significantly increases heat loss through evaporative cooling 1
• Evaluate for nocturnal enuresis: This is a specific risk factor for hypothermia during sleep in psychiatric and general populations 2

Medication-Induced Hypothermia Risk

Several medication classes commonly cause hypothermia during sleep and must be reviewed immediately 2:

• Antipsychotic medications (major risk factor)
• Benzodiazepines and other sedatives
• Beta-adrenergic antagonists
• These medications impair thermoregulation and increase hypothermia risk, particularly when combined with environmental cold exposure 2

Medical Conditions to Screen For

• Peripheral vasospastic syndrome: Cold extremities with thermal discomfort affects 31.1% of women and 6.9% of men, and is strongly associated with sleep initiation difficulties 3
• Hypothyroidism: Impairs metabolic heat production 4
• Hypoglycemia: Reduces metabolic rate and heat generation 4
• Autonomic dysfunction: Impairs temperature perception and regulation 4, 2
• Seizure disorders: Increase hypothermia risk during sleep 2
• Debilitating physical illness or mental retardation: Both increase vulnerability 2

Clinical Staging and Symptoms

If True Hypothermia is Present (Core Temperature <35°C)

Mild hypothermia (32-35°C) 1:

• Altered level of responsiveness
• Shivering present
• Patient may be confused or uncoordinated 1

Moderate hypothermia (28-32°C) 1:

• Decreased level of responsiveness (responds only to loud voice or pain)
• Shivering may or may not be present
• This is a medical emergency requiring immediate activation of emergency services 1

Severe hypothermia (<28°C) 1:

• Unresponsive, may appear lifeless
• Cessation of shivering
• Slow heart rate and breathing
• High risk for cardiac arrhythmias and arrest 1

Treatment Algorithm

For Cold Sensation Without True Hypothermia (Most Common Scenario)

Step 1: Environmental Modification 1:

• Increase room temperature to 20-22°C (68-72°F)
• Use dry, insulating blankets with multiple layers
• Cover head and neck, as significant heat loss occurs from these areas 1
• Ensure bedding remains dry throughout the night 1

Step 2: Medication Review 2:

• Consult prescribing physician about adjusting or discontinuing medications known to impair thermoregulation
• Do not stop psychiatric medications abruptly without medical supervision 2

Step 3: Address Peripheral Vasoconstriction 3:

• Warm extremities before bed (warm bath, heated socks)
• This improves distal vasodilation and may reduce sleep onset difficulties 3

For Confirmed Mild Hypothermia (32-35°C)

Passive and active rewarming should be used together 1:

• Remove from cold environment immediately 1
• Remove any wet or damp clothing 1
• Apply dry blankets for passive rewarming 1
• Use active rewarming with heating devices if available (chemical heat packs, forced air warming) 1
• Place insulation between heat source and skin to prevent burns 1
• Monitor frequently for burns and pressure injury 1
• Provide high-calorie foods or drinks if patient is alert and can safely swallow 1

For Moderate to Severe Hypothermia (≤32°C)

This is a life-threatening emergency 1:

• Activate emergency medical services immediately 1
• Begin rewarming by any available method while awaiting transport 1
• Handle patient gently to avoid triggering cardiac arrhythmias 1
• Use all available passive and active rewarming methods simultaneously 1
• Do not delay transport for rewarming 1

Critical Pitfalls to Avoid

• Do not use body-to-body rewarming: This is not beneficial compared to chemical heat packs or forced air systems 1
• Do not apply heat sources directly to skin: Always place insulation between heat source and skin 1
• Do not ignore medication effects: Air conditioning combined with sedating medications significantly increases hypothermia risk 2
• Do not dismiss cold extremities as benign: This symptom doubles the risk of sleep initiation difficulties and may indicate underlying vasospastic syndrome requiring treatment 3
• Do not assume psychiatric patients are exaggerating symptoms: Hypothermia is a documented risk in this population and has been linked to sudden unexplained death in patients on antipsychotics 2

When to Seek Immediate Medical Attention

Activate emergency services if any of the following are present 1:

• Decreased level of responsiveness (unresponsiveness, inability to remain awake, mumbling speech, confusion)
• Inability to participate in removal of clothing
• Pallor, cyanosis, or frozen skin
• Stumbling or inability to coordinate movements
• Core temperature <32°C if measurable 1