Heat syncope

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Heat syncope
A casualty at the Olympic Games, London, 1948. (7649953728).jpg
A Boy Scout at the 1948 Olympic Games faints in the intense heat
Classification and external resources
Specialty emergency medicine
ICD-10 T67.1
ICD-9-CM 992.1

Heat syncope is fainting or dizziness as a result of overheating (syncope is the medical term for fainting). It is a type of heat illness. The basic symptom of heat syncope is fainting, with or without mental confusion.[1] Heat syncope is caused by peripheral vessel dilation, resulting in diminished blood flow to the heart and dehydration.


Heat syncope occurs in a warm environment when blood pressure is lowered as the body dilates (widens) arterioles (small blood vessels) in the skin to radiate heat. This condition occurs within five days of heat acclimatization, before the blood volume expands.[2] The result is less blood to the brain, causing light-headedness and fainting when a person stands up quickly or stands for a long period of time. Those who perform strenuous work outside in warm climates are at particular risk.[3]


The basic treatment for heat syncope is like that for other types of fainting: the patient is positioned in a seating or supine position with legs raised. Water is administered slowly, and the patient is moved to a cooler area.

The affected person should rest and recover, because heat syncope can lead to heat stroke or heat exhaustion.[3]


  1. ^ http://www.ncbi.nlm.nih.gov/pmc/articles/PMC164365/
  2. ^ http://www.sportsci.org/encyc/drafts/Heat_acclimatization/heataccl.doc
  3. ^ a b Jacklitsch, Brenda L. (June 29, 2011). "Summer Heat Can Be Deadly for Outdoor Workers". NIOSH: Workplace Safety and Health. Medscape and NIOSH.