From the Research
A body temperature of 40°C (104°F) is a serious medical emergency requiring immediate attention, and someone can typically sustain this temperature for only a few hours before risking severe complications or death. At this temperature, proteins in the body begin to denature, affecting cellular function and potentially causing organ damage, particularly to the brain. The most recent and highest quality study on this topic is not directly available, but based on the available evidence, it is clear that fever is a complex physiologic response that can have both beneficial and harmful effects on the body 1.
Some studies suggest that antipyretic therapies may not be effective in reducing the duration of illness and may even prolong it 2. However, in the context of a life-threatening condition such as a body temperature of 40°C, the primary concern is to reduce the temperature and prevent organ damage. Immediate cooling measures should be initiated, including removing excess clothing, applying cool compresses to the neck, armpits, and groin, and seeking emergency medical care. Medical professionals will likely administer IV fluids and medications such as acetaminophen or ibuprofen to reduce fever.
The underlying cause, whether infection, heat stroke, or medication reaction, must be identified and treated. Prolonged exposure to temperatures this high can lead to seizures, coma, permanent neurological damage, or death. The very young, elderly, and those with chronic conditions are at even greater risk of complications from such high temperatures. It is also important to note that mild thermotolerance induced at a fever temperature of 40°C can protect cells against hyperthermia-induced apoptosis mediated by death receptor signalling 3.
In terms of the duration that someone can sustain a temperature of 40°C, it is generally agreed that this is a short period, typically only a few hours, before severe complications or death can occur. The exact duration will depend on various factors, including the individual's overall health, the underlying cause of the fever, and the effectiveness of treatment. However, based on the available evidence, it is clear that prompt medical attention is essential to prevent serious complications and improve outcomes 4, 5.
Key considerations in managing a body temperature of 40°C include:
- Immediate cooling measures to reduce the temperature
- Administration of IV fluids and medications to reduce fever
- Identification and treatment of the underlying cause
- Close monitoring of the individual's condition to prevent complications
- Consideration of the individual's overall health and risk factors for complications.