Doctors Warn of Heatstroke: Hot Body Without Sweating Is a Dangerous Sign

Thailand, 28th Apr 2026 – Amid continuously rising temperatures caused by extreme heat and global heatwaves, a critical health risk that should not be overlooked is heatstroke. This condition is becoming increasingly common during hot weather, especially among high-risk groups such as the elderly, young children, outdoor workers, and individuals with underlying conditions like heart disease, diabetes, and hypertension.

Heatstroke is not just general heat exhaustion—it is a medical emergency. It occurs when the body is unable to dissipate heat effectively, causing a rapid rise in body temperature that disrupts the function of vital organs, particularly the brain and heart. Without timely treatment, it can lead to severe complications or even death.

Dr. Suresh Kumar Narula, a specialist in cardiology, critical care medicine, coronary artery disease, and diagnostic angiography at Praram 9 Hospital, explains:

“Heatstroke occurs when the body temperature rises above 40–40.5°C, reaching a critical level. The brain’s temperature regulation system fails, and the body can no longer release heat through sweating. As a result, the patient’s skin becomes extremely hot but dry, with no sweat. Internal organs begin to suffer damage immediately.”

A key warning sign of heatstroke is a body temperature above 40.5°C without sweating, despite intense heat. This indicates failure of the brain’s temperature control system. The brain is the most heat-sensitive organ—once the temperature exceeds this threshold, brain cells begin to shut down. Patients may experience confusion, seizures, or loss of consciousness. This triggers a domino effect, where damage rapidly spreads to the heart, liver, and kidneys, causing acute inflammation.

In severe cases, this may lead to Disseminated Intravascular Coagulation (DIC)—a dangerous condition involving abnormal blood clotting throughout the body, which can be life-threatening.

Dr. Suresh emphasizes that the key to treating heatstroke is time:

“Every minute counts. The faster we can lower the body temperature, the higher the chance of survival. This principle is similar to ‘Time is Brain’ or ‘Time is Muscle’ in stroke and heart attack patients.”

Heatstroke affects the entire body. The heart may develop serious arrhythmias due to electrical disturbances. While it may not stop immediately like in cardiac arrest, delayed treatment can lead to heart failure. At the same time, patients may suffer acute kidney failure, severe liver damage, and abnormal blood clotting, accelerating multi-organ failure.

High-risk groups for heatstroke include:

1. Individuals with weakened physical conditions, such as children, the elderly, and patients with chronic diseases (especially heart disease, diabetes, and hypertension) 

2. Healthy individuals engaging in intense outdoor activities, during the afternoon hours when heat is intense such as athletes or laborers

Patients with heart disease and diabetes are particularly vulnerable because their bodies already have underlying weaknesses. When exposed to extreme heat, these organs are affected first, leading to faster and more severe complications. If hospital treatment is delayed, survival rates may drop below 50%.

First Aid for Suspected Heatstroke:

If someone is suspected of having heatstroke, the most important action is to seek immediate medical attention.

• Move the patient to a shaded or air-conditioned area 

• If conscious, allow them to drink cool water 

• Generally, the heart is still beating, so CPR is not the primary first aid unless the patient has stopped breathing 

The priority is to get the patient to the nearest hospital as quickly as possible. Every minute is critical. With prompt treatment, recovery to normal life is possible.

Dr. Suresh also clarifies a common misconception:

Many people confuse heatstroke with stroke due to similar symptoms. However, the causes are entirely different.

• Stroke is caused by blocked or ruptured blood vessels in the brain, leading to lack of blood and oxygen 

• Heatstroke is caused by excessive heat overwhelming the body’s temperature regulation system 

Stroke symptoms include facial drooping, arm weakness, slurred speech, and vision problems—commonly remembered with the FAST (Face, Arm, Speech, Time) principle.

In contrast, heatstroke is characterized by extreme body heat without sweating, along with neurological symptoms such as confusion, delirium, seizures, or unconsciousness.

Prevention Tips:

• Stay well-hydrated throughout the day 

• Avoid outdoor exposure between 11:00 AM – 3:00 PM, when temperatures are highest 

• Maintain good health through proper nutrition and regular exercise (at least 5 days per week, 30–40 minutes per session) 

For more information about heatstroke, please contact the Cardiovascular Institute at Praram 9 Hospital or call +66 (0) 2202-9999, or reach us via Facebook: @Praram9Hospital.International

Contact: For more information, please contact the Cardiovascular Institute at Praram 9 Hospital

Tel: +66 (0) 2202-9999

Facebook: @Praram9Hospital.International

Company Details

Organization: FOUR HUNDRED Co., Ltd.

Contact Person: Ms. Jeerasuda Chittrakron

Website: https://praram9.com/en

Email: Send Email

Country: Thailand

Release Id: 28042644474