Why Anorexia Causes Cold Intolerance: The Physiology

Cold intolerance is a direct consequence of starvation physiology in anorexia nervosa:

1. Loss of insulating fat: Subcutaneous fat traps heat; depletion → rapid heat loss.
2. Reduced metabolic rate: Adaptive thermogenesis lowers basal heat production by 20–30%.
3. Thyroid downregulation: Low T3 syndrome (euthyroid sick) reduces thermogenesis.
4. Peripheral vasoconstriction: Sympathetic overdrive shunts blood from skin to core → cold hands/feet.
5. Hormonal disruption: Low estrogen, testosterone, leptin impair thermoregulation.
6. Loss of muscle mass: Muscle generates heat at rest; atrophy reduces this source.

Clinical Significance

• Persistent coldness signals severe energy deficit.
• Improves with weight restoration and metabolic recovery.
• May persist months after weight normalization due to lingering hormonal adaptation.

Addressing cold intolerance requires nutritional rehabilitation, not external warming alone.