Within hours of sunrise, the two-room flats in the government-constructed apartment in New Rajarajeshwari Peta in Vijayawada feels like a pot on a stove.

By 11 am, Vidya (name changed) sits outside her home with her neighbours under the shade of a tree. The women chat and laugh, relieved to escape the summer heat inside the house. Vidya who is in her late 30s lives on the ground floor or a four-storey building, in a resettlement colony constructed more than a decade ago for low income families.

“Ee vadagaalpula valla intlo baaga aaviri vachesthundi. With these hot winds, heat builds up in the house like steam. I find it difficult to breathe sometimes,” she said.

But for Vidya, it is more than just physical discomfort. She is diabetic and feels her condition worsen during the summer. Extreme heat is known to exacerbate health risks of those living with chronic diseases.

About 57 percent of Indian districts, home to 76 percent of the country’s population, are at high to very high heat risk, a 2025 study by Council on Energy, Environment and Water (CEEW) showed. Andhra Pradesh is among the most heat-prone states.

A study done by the India Meteorological Department’s scientists published this year shows that the average maximum temperature across India increased by ~0.5°C by 2000, and by ~1.0°C by 2020. Northwestern and central India and the coast of Andhra Pradesh experienced the most significant increase. Between 1981 and 2000, these regions experienced an average of 2.5 to 5.5 heatwave days per year.

However, over the two decades between 2001-2020, the frequency of heatwaves has increased with 3.5-8.5 days per year, particularly in northern, western, south-central, central-east, and peninsular India.

IMD has forecast heatwave to severe heatwave conditions in 17 states and Union territories, including parts of Andhra Pradesh such as Vijayawada and Guntur.

IndiaSpend reached out to the Union and state health ministries for comment. We will update this story when we receive a response.

How heat affects those with comorbidities

“The body’s homeostatic mechanism, meaning how we adapt to any change in our external environment, such as high heat, becomes impaired in those with chronic diseases like hypertension, diabetes, renal disease, among others,” said Vivekanand Jha, executive director at The George Institute for Global Health, India, and a nephrologist and public health researcher.

For blood pressure patients, excessive sweating can lead to a drop in blood pressure. “We have seen in clinics that people with well-controlled hypertension suddenly experience low blood pressure during extreme heat. They become giddy and weak. And when we measure their blood pressure, it is low. So, during the summer months, we have to reduce the number of blood pressure medicines, especially diuretics, which increase the urine flow, increasing loss of fluid,” Jha added.

Diabetics are at greater risk for heat-related illnesses because of their impaired capacity to dissipate heat, and this can have important consequences on cardiovascular regulation and glycemic control.

For insulin-dependent diabetics, during extreme heat, the body is unable to absorb insulin, resulting in uncontrolled sugar levels. “Insulin needs refrigeration at 4 degrees Celsius. Many in informal settlements don't have access to a fridge, so obviously they don't have access to effective insulin.,” Jha explained.

In renal disease, the loss of salt and water due to excess heat can result in loss of kidney function. “Let's say a manual worker goes out to work in extreme heat from morning to........

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