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Fainting and the Summer Heat

Dr. Hira Tanveer

2 min read

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Fainting, known in the medical world as ‘Syncope’, is the involuntary and sudden loss of consciousness in a person as a result of various internal (blood pressure changes) and external factors, such as standing for long periods of time, standing suddenly, fear, pain, and prolonged sun exposure; which is then known as ‘Heat Syncope’. However, before we go into the details of heat syncope, let us first understand how one faints.

The Fainting Mechanism:

Normally, for any of the above situations, the body succeeds in maintaining blood pressure by constricting blood vessels, increasing heart rate, and releasing relevant hormones into the bloodstream, as a result, the brain remains oxygen-enriched and the body continues its functioning. However, due to some triggers, the body fails to regulate blood pressure, causing reduced blood flow to the brain and increased blood flow to the legs due to blood vessel dilation (expansion) instead of contraction, eventually resulting in a temporary ‘fainting episode’.

Heat, Blood Pressure, and Fainting:

Standing or physical overexertion for prolonged time periods in high temperatures triggers a cooling mechanism in the body that involves blood vessel dilation, decelerated heart contractions, low blood pressure, and reduced brain oxygen levels, resulting in what is termed as a ‘heat syncope’ that mimics the effects of a ‘fainting spell’. In its mild form, affected individuals usually regain consciousness 10-15 minutes after fainting, with all body functions restored. However, some cases require immediate medical attention in order to avoid a possibly deadly heat stroke.


A heat syncope usually follows two or more of the following symptoms:

  • Lightheadedness, particularly when changing positions
  • Nausea, sweating, and abdominal discomfort
  • Pale, cool, and moist skin
  • Increased pulse rate
  • Restlessness

Who Can Get It?

Heat syncope can affect anyone regardless of heart health. However, the risk is magnified for those unaccustomed to higher temperatures or hot climates, along with dehydration. Moreover, soldiers standing guard during daytime are also highly susceptible to heat syncope, as even slight movements after long standing periods can contract leg muscles and rush previously pooled blood from the legs to the heart and head, resulting in fainting. The same can be said for construction workers who work during the day.

Emergency Protocol:

Since heat syncope can quickly progress into heat stroke or other serious heat-related conditions, quickly raise the patient’s legs to increase blood flow to the brain, move them to a cool, shady place, and check their airways, breathing and blood circulation. Give them water or an electrolytic sports drink as soon as they regain consciousness.


  • Stay well-hydrated, eat frequent meals, and avoid hot showers entirely.
  • Remember to periodically shift your weight from one leg to another if you have to stand for prolonged time periods.
  • Cross your legs and clench your buttock and leg muscles when you start feeling lightheaded to prevent fainting, while also avoiding sudden posture changes.
  • Eat a banana, boiled egg, or sweet potato when in danger of fainting. Also carry nuts for instant energy replenishment when you feel dizzy or feel that your sugar levels are dropping.
  • To control blood pressure, drink a glass of lemon juice with sugar and black salt.
  • Since vitamin B deficiency is linked with heat syncope, drink two strong cups of aniseed (saunf) tea daily.
  • Consult a doctor for relevant medication or dietary changes, such as increased salt and water intake, if you faint frequently.

Although heat syncope is fairly common, it may sometimes be a symptom of an underlying cardiovascular, metabolic, or nervous system disorder. Make sure to get properly checked by your physician after suffering from a syncope. You can also book an appointment with a top General Physician in Lahore, Multan and Islamabad through oladoc.com, or call our helpline at 042-3890-0939 for assistance to find the RIGHT Doctor for your health-related concerns.

Disclaimer: The contents of this article are intended to raise awareness about common health issues and should not be viewed as sound medical advice for your specific condition. You should always consult with a licensed medical practitioner prior to following any suggestions outlined in this article or adopting any treatment protocol based on the contents of this article.

Dr. Hira Tanveer
Dr. Hira Tanveer - Author "Dr. Hira Tanveer is an MBBS doctor and currently serving at CMH Lahore. Writing is her favorite hobby as she loves to share professional advice on trendy healthcare issues, general well-being, healthy diet, and lifestyle.

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