Heatwave tips: With heatwave alerts across India, experts warn of rising health risks. A doctor explains why extreme heat stresses the body, who is most vulnerable, and essential do’s and don’ts to prevent heatstroke, dehydration, and organ damage.
India is once again grappling with intense heatwave conditions, with temperatures crossing 40 degrees Celsius in several states as early as April. The India Meteorological Department (IMD) has issued multiple alerts, warning of prolonged heat exposure risks and urging precaution, particularly for vulnerable groups. While heat may seem like a seasonal inconvenience, medical experts stress that extreme temperatures can have serious, even life-threatening consequences. Heatwaves place enormous strain on the human body, affecting the cardiovascular system, kidneys, brain, and metabolism.
“Extreme heat is not just discomfort. It’s a multi-organ stressor affecting the heart, brain, kidneys, and metabolism,” explains Dr Sanjay Verma, Senior Consultant, Internal Medicine, Fortis Escorts, Okhla, Delhi. What makes early-season heat particularly dangerous is the body’s lack of acclimatisation. Combined with urban heat island effects, dehydration, and chronic illnesses, heatwaves can significantly increase the risk of heat exhaustion, heatstroke, and long-term health complications.
Understanding how heat affects the body, and how to respond, can be lifesaving.
Why Early Heatwaves Are More Dangerous
“Early-season heatwaves are more dangerous because the body hasn’t acclimatised yet,” says Dr Verma. In April, the body is still in a “winter-adjusted” state:
- Sweating starts later
- Salt loss is higher
- Blood circulation is less efficient
“By May-June, the body adapts by sweating earlier and more efficiently and maintaining better circulation,” he explains. This means a 45 degrees Celsius day in April can put sudden stress on the cardiovascular system, increasing risks of dehydration, fainting, and heatstroke. Rapid temperature spikes are associated with increased mortality during heatwaves.
Why Your Body Works Harder In Extreme Heat
At temperatures above 40 degrees Celsius, the body expends more energy simply to stay cool. “Skin vasodilation forces the heart to pump harder, sweating requires energy, and the brain constantly regulates temperature,” says Dr Verma.
Key physiological responses include:
- Increased heart workload (similar to mild continuous exercise)
- Kidney strain to conserve water
- Activation of heat-shock proteins to protect cells
