Heatwave pushes surge in illness as doctors warn against ignoring early symptoms

As temperatures soar past 40 degrees Celsius across several parts of the country, doctors are reporting a sharp rise in heat-related illnesses, ranging from dehydration and heat exhaustion to life-threatening heatstroke. Experts warn that most cases are preventable if early symptoms are not ignored.

Hospitals are witnessing a steady influx of patients experiencing dizziness, fatigue, nausea and muscle cramps—early signs of heat exhaustion that often go unnoticed.

“One of the most common concerns people are experiencing during the current heatwave is unusual tiredness, dizziness, or nausea after being out in the sun. This is typically heat exhaustion, and it is now being seen even in individuals who otherwise consider themselves healthy,” said Dr Vandana Boobna, Director Internal Medicine Max Super Speciality Hospital Shalimar Bagh.

In more serious cases, patients are arriving with high body temperatures, confusion and fainting episodes—clear indicators of heatstroke.

Rising burden on health systems

Doctors say dehydration continues to be one of the most widespread issues, often worsened by long commutes, outdoor work and inadequate fluid intake.

“Many people are simply not drinking enough fluids. By the time they seek help, they are already dealing with weakness, muscle cramps, or reduced urine output,” Boobna said.

“The most common issues during the current heatwave are dehydration, heat exhaustion, and heatstroke. Many people also report headaches, dizziness, and low blood pressure, along with a rise in stomach infections,” said Dr Manjusha Agarwal, Consultant Internal Medicine Gleneagles Hospital Mumbai.

Highlighting the paediatric impact, Dr Nishant Bansal, Consultant Paediatrician and Neonatologist Motherhood Hospitals Noida, said, “In children, dehydration, heat exhaustion, stomach infections, and increased cases of fatigue and irritability are commonly seen due to prolonged heat exposure.”

Doctors also point to a rise in gastrointestinal infections as high temperatures accelerate food spoilage.

“There has been a steady increase in patients suffering from dehydration, dizziness, headaches, nausea, fatigue, and excessive sweating, and in severe cases low blood pressure and electrolyte imbalance,” said Dr Sunil Rana, Associate Director and Head Internal Medicine Asian Hospital.

Strain on chronic conditions

Experts warn that extreme heat places additional stress on the body’s thermoregulatory system, worsening existing illnesses.

“As temperatures exceed 40°C, the body’s cooling mechanisms become overwhelmed, increasing cardiovascular strain and exacerbating risks in patients with hypertension, heart disease, diabetes, and chronic kidney disease,” said Dr Pankaj Khatana, Senior Consultant Internal Medicine Marengo Asia Hospitals Gurugram.

“Heatwaves amplify chronic conditions, triggering respiratory exacerbations, cardiac events, and dehydration-related kidney injury,” he added.

“Being in the heat all the time makes it harder to sleep and worsens existing conditions like heart and kidney problems,” said Dr Seema Dhir, Senior Consultant Internal Medicine Artemis Hospitals.

Early symptoms often ignored

Doctors stress that early warning signs are frequently overlooked, allowing conditions to worsen.

“These include persistent dizziness, weakness, nausea, muscle cramps, unusual fatigue, confusion, or fainting episodes,” Boobna said.

“Heavy sweating, weakness, headache, nausea, and dizziness are early signs of heat exhaustion. If not addressed, it can progress to heatstroke,” Dhir said.

“Excessive sweating with cold or clammy skin, persistent headache, dizziness, muscle cramps, nausea, and a rapid or weak pulse are early indicators that require prompt attention,” said Dr Vamshi V, Consultant Internal Medicine Gleneagles AWARE Hospital Hyderabad.

Dr Mohammad Nadeem, Head of Emergency Fortis Memorial Research Institute Gurugram, warned, “Extreme weakness, vomiting, abdominal cramps, palpitations, and a very warm body should not be ignored. If neglected, these can lead to heatstroke, where the patient may become unconscious with very high temperature.”

Who is most at risk

While heat waves affect everyone, certain groups are significantly more vulnerable.

Outdoor workers such as construction labourers, delivery personnel and traffic police face prolonged exposure to direct sunlight.

“Outdoor workers face prolonged exposure, often without adequate hydration or rest, increasing their risk of dehydration and heatstroke,” Boobna said.

Children and the elderly are particularly at risk due to reduced ability to regulate body temperature.

“Young children, particularly infants, are most at risk as their bodies cannot regulate temperature well and depend on adults for hydration,” Bansal said.

“Two extremes of age—paediatric and elderly populations—as well as patients with comorbid conditions like heart or kidney disease are at highest risk,” Nadeem added.

People with chronic illnesses are also more vulnerable.

“Elderly individuals, children, outdoor workers and those with chronic illnesses like diabetes or heart disease are most at risk, as their bodies either cannot regulate temperature well or lose fluids faster,” Agarwal said.

Prevention is key

Doctors emphasise that simple precautions can significantly reduce risks.

“Stay well hydrated throughout the day and do not rely only on thirst,” Boobna advised.

“Keep yourself hydrated, avoid prolonged exposure to direct sunlight, take proper breaks, and wear light, loose cotton clothes,” Nadeem said.

“Drink water or oral rehydration solutions regularly, avoid peak heat hours and stay in cool environments,” Vamshi added.

Experts also advise avoiding heavy meals, limiting outdoor activity during peak hours and ensuring proper ventilation indoors.

When it becomes a medical emergency

A heat-related condition becomes critical when it progresses to heatstroke.

“In heatstroke, the body cannot regulate its temperature. Patients may present with confusion, seizures, coma, and extremely high temperature,” Khatana said, noting that complications can include multi-organ failure.

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“Warning signs include very high body temperature, confusion, fainting, seizures, and hot, dry skin,” Vamshi said.

Nadeem cautioned that “heatstroke can lead to arrhythmias, cardiac arrest, and even death if not treated immediately.”

Doctors underline that rapid cooling and urgent medical care are essential at this stage.

With heatwaves becoming more frequent and intense, experts stress that awareness and early action remain the first line of defence.

“Most heat-related illnesses are preventable with awareness and timely action,” Boobna said, adding that recognising early symptoms and making small changes in daily routine can save lives.