Wet bulb temperature is not the regular temperature we see on weather apps. It is a measure that combines heat and humidity to show how stressful the environment actually feels to the human body. “During extreme humidity, sweat does not evaporate properly, which means the body struggles to cool itself. That is why even temperatures in the mid-30s can start feeling dangerous when humidity is high,” said Dr Sundar Krishnan, senior consultant, internal medicine, KIMS Hospitals, Thane.
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.
Notably, the body depends on sweating to maintain a stable internal temperature. When humidity rises sharply, sweat cannot evaporate efficiently. “This traps heat inside the body and increases the risk of dehydration, heat exhaustion, muscle cramps, dizziness, and in severe cases, heatstroke. Once the body loses its ability to cool down effectively, it can become a medical emergency very quickly,” described Dr Sundar.
Persistent fatigue, intense thirst, headache, nausea, confusion, rapid heartbeat, excessive sweating followed by dry skin, and reduced urination are early warning signs. “Many people ignore these symptoms, thinking it is ‘normal summer tiredness’, but delayed action can worsen the condition rapidly,” said Dr Sundar.
Dr Harish Chafle, senior consultant chest physician, bronchoscopist, intensivist, and sleep disorders specialist at Gleneagles Hospitals, Parel, Mumbai, cautioned that during heatwaves, a high wet-bulb temperature can be dangerous, especially for older adults, children, outdoor workers, and people with heart or kidney problems. “Even if the actual temperature is not extremely high, high humidity can make the body feel hotter and increase the risk of dehydration, heat exhaustion, and heatstroke.”
Keep drinking water (Photo: Getty Images/Thinkstock)
How is it calculated?
Traditionally, it is measured using a thermometer wrapped in a wet cloth. “As water evaporates, the temperature drops. But if the air already contains a lot of moisture, evaporation slows down, and the reading remains high. Today, weather agencies use advanced calculations involving humidity, air temperature, wind speed, and atmospheric pressure to estimate wet bulb temperatures more accurately,” said Dr Sundar.
What helps?
Hydration is critical, but water alone may not always be enough during prolonged sweating. “People should also replenish electrolytes, avoid outdoor activity during peak afternoon hours, wear loose cotton clothing, and stay in well-ventilated or air-conditioned spaces whenever possible. Elderly individuals, children, outdoor workers, and people with chronic illnesses need extra caution because they are more vulnerable to heat-related complications,” said Dr Sundar.
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Dr Chafle added that it is important to avoid direct sunlight, wear loose cotton clothes, stay indoors during peak afternoon hours, and use fans or air conditioning whenever possible. “Wet bulb temperature is an important warning sign during heatwaves. Monitoring both heat and humidity can help people protect themselves from serious heat-related illnesses and stay safe during extreme weather conditions.”
DISCLAIMER: This article is based on information from the public domain and/or the experts we spoke to. Always consult your health practitioner before starting any routine.