The Hidden Dangers of Extreme Heat: How 45°C+ Temperatures Affect Your Organs
Across much of India, including the Delhi-NCR region, temperatures have soared past 45°C, creating a severe heatwave that shows no signs of easing. The India Meteorological Department (IMD) predicts that maximum temperatures will remain between 43°C and 45°C for several more days, offering little respite. While the discomfort of such heat is obvious, the real threat lies in how it silently damages internal organs. Health experts warn that extreme heat does not just make daily life uncomfortable—it places immense strain on the heart, liver, kidneys, and brain, particularly for vulnerable groups.
Why Extreme Heat Is So Dangerous for the Body
When external temperatures climb well above the body’s natural core temperature of around 37°C, the body must work overtime to cool itself. This extra effort forces the heart to pump faster, accelerates fluid loss through sweating, and depletes essential electrolytes. According to the World Health Organization (WHO), the elderly, children, pregnant women, outdoor workers, and those with chronic illnesses are most at risk. As the mercury hits 45°C and beyond, the body’s blood circulation pattern shifts dramatically. More blood is directed toward the skin to release heat, which in turn places added pressure on vital organs such as the heart, kidneys, and brain. Persistent dehydration also thickens the blood, potentially disrupting blood pressure and oxygen delivery throughout the body.
The Cardiovascular System Under Siege
The heart is often the first organ to feel the impact of extreme heat. When temperatures exceed 45°C, the body redirects blood flow to the skin in an effort to cool down. This forces the heart to work harder than usual, increasing both heart rate and the workload on the cardiovascular system. Research from the American Heart Association indicates that prolonged exposure to high heat can elevate heart rate significantly, raising the risk of heart attacks and strokes. Dehydration compounds this problem by causing a drop in critical electrolytes like sodium and potassium, which are essential for maintaining a steady heartbeat and proper muscle function. Without these micronutrients, the heart becomes vulnerable to arrhythmias and other serious complications.
Liver Damage in the Heat
The liver, too, suffers under extreme heat conditions. Studies have shown that heat stress and heat stroke can cause a spike in liver enzymes, signaling potential damage to this vital organ. Dehydration reduces blood flow throughout the body, and the liver is no exception. When circulation is compromised, the liver receives less oxygen and fewer nutrients, impairing its ability to detoxify the blood and regulate metabolism. Prolonged exposure to intense heat can lead to inflammation, swelling, and even cellular damage within the liver. For individuals with pre-existing liver conditions, the risks are even greater, as the organ’s capacity to cope with additional stress is already limited.
Kidney Health at Risk
Kidneys are particularly vulnerable during heatwaves. Senior nephrologist Dr. Vrikam Malha explains that continuous exposure to high temperatures leads to excessive sweating, which depletes the body of fluids and electrolytes. Dehydration reduces blood flow to the kidneys, impairing their ability to filter waste and maintain fluid balance. According to the National Kidney Foundation, people who work outdoors in hot conditions face a significantly higher risk of kidney disease. As the body loses water, urine becomes more concentrated, increasing the likelihood of mineral and sodium crystal formation. These crystals can accumulate and develop into kidney stones, a painful condition that becomes more common during summer months. In severe cases, repeated heat stress can lead to acute kidney injury or chronic kidney disease over time.
Brain Function and Heat Stress
The brain is highly sensitive to changes in body temperature and hydration. When the body overheats, blood flow is redirected away from internal organs toward the skin, which can reduce oxygen supply to the brain. This may result in confusion, dizziness, headaches, and impaired judgment—early signs of heat exhaustion. If left unchecked, heat stroke can set in, causing the brain’s temperature regulation center to fail. This medical emergency can lead to seizures, loss of consciousness, and even permanent neurological damage. Children and the elderly are especially susceptible because their bodies are less efficient at regulating temperature.
Who Is Most at Risk?
While extreme heat poses a threat to everyone, certain groups face greater danger. Older adults have a reduced ability to sense thirst and regulate body temperature, making them prone to dehydration and heat-related illnesses. Children’s bodies heat up faster and cool down more slowly, putting them at higher risk. Pregnant women experience increased blood volume and metabolic demands, which can be exacerbated by heat stress. Outdoor workers, such as construction laborers and farmers, face prolonged exposure without adequate cooling breaks. People with chronic conditions like diabetes, hypertension, or heart disease are also more vulnerable, as their bodies already struggle to maintain balance under normal conditions.
Practical Steps to Protect Your Organs
Staying safe during a heatwave requires proactive measures. Drink plenty of water throughout the day, even if you do not feel thirsty, to prevent dehydration. Avoid caffeinated or sugary beverages, as they can worsen fluid loss. Wear lightweight, light-colored clothing and a wide-brimmed hat when outdoors. Limit physical activity during peak heat hours, typically between noon and 4 p.m. Use fans, cool showers, or damp cloths to lower body temperature. For those with underlying health conditions, consult a doctor about adjusting medications or activity levels during extreme heat. Recognize early warning signs such as excessive sweating, weakness, nausea, or confusion, and seek medical help immediately if symptoms escalate.
The Bigger Picture: Climate Change and Rising Temperatures
As global temperatures continue to climb due to climate change, heatwaves are becoming more frequent and intense. This trend poses a growing public health challenge, particularly in regions like South Asia where infrastructure and healthcare systems may struggle to cope. Understanding the specific ways in which extreme heat affects the body’s organs is crucial for prevention and timely intervention. By taking individual and community-level precautions, it is possible to reduce the burden of heat-related illnesses and protect the most vulnerable members of society.
