As we begin to experience intense heatwaves across India, there has been a new health phenomenon making headlines. Earlier, the impact of heatwaves was commonly associated with heat stroke and dehydration, but a seasonal rise in Acute Kidney Injury (AKI) has been witnessed in recent years during peak summer months.
Summer is emerging as a renal health risk in India
Our kidneys rely heavily on adequate blood flow and hydration to perform their functions smoothly, but they are extremely vulnerable to severe heatwaves. During hot temperatures above 40°C and high humidity, the body loses a significant amount of fluid through sweating, which is why it’s very important to keep ourselves hydrated. So, when we don’t replace the fluids adequately, our blood volume may drop along with a dip in the blood pressure, causing a decrease in the blood flow to the kidneys. Known as a pre-renal cause of acute kidney injury, this is the most common form of phenomenon during extreme heatwaves.
If dehydration persists, it can progress to intrinsic (renal) injury, where the kidney tissue itself gets damaged due to sustained low perfusion. In severe heat stroke, muscle breakdown (rhabdomyolysis) releases myoglobin into the bloodstream, which can directly injure kidney tubules.
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Although many cases of heat-related AKI are reversible with early treatment, repeated episodes can cause cumulative damage. Over time, this may accelerate Chronic Kidney Disease (CKD). This pattern, sometimes described as “heat stress nephropathy,” is increasingly observed among outdoor workers exposed to extreme temperatures for years.
States such as Rajasthan, Gujarat, Telangana, Andhra Pradesh, Karnataka, Delhi, and parts of Uttar Pradesh frequently report severe heatwaves. Agricultural labourers, construction workers, traffic police personnel, factory workers, and street vendors face prolonged sun exposure and are at high risk. People with diabetes, hypertension, heart disease, pre-existing kidney disease, and the elderly are particularly vulnerable because their kidneys have limited reserve.
Look for the early warning signs
If the symptoms of the disease are ignored and treatment is delayed, severe kidney problems may arise, which might lead to hospitalisation and even dialysis. Reduced urine production, dark urine, intense thirst, exhaustion, light-headedness, cramping in the muscles, nausea, or disorientation are typical symptoms. Urinary tract infection is another complication that may arise from dehydration. Decreased urine output increases the risk of developing kidney stones.
How can we prevent it?
Simple prevention strategies can be adhered to avoid this:
*Drink adequate fluids regularly throughout the day.
*Use oral rehydration or electrolyte-balanced drinks during heavy sweating.
*Avoid going out during peak afternoon heat.
*Ensure shaded rest breaks for outdoor workers.
As we are expecting intensified summers, kidney protection must become part of public health awareness. Heatwaves are no longer just a weather concern or a result of global warming; they are an emerging threat to renal health in India.
This article is authored by Dr Vinod Kumar K, Consultant - Nephrology, Manipal Hospital.
The opinions expressed in this article are those of the author and do not purport to reflect the opinions or views of THE WEEK.