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Rising global temperatures and more frequent heatwaves may pose a growing threat to kidney health, with recent studies suggesting that prolonged exposure to extreme heat can increase the risk of chronic kidney disease (CKD). Researchers say the effects are particularly concerning for older adults and people with existing health conditions.

Heatwaves linked to declining kidney function

A study published in the journal BMC Nephrology found that heatwaves have emerged as an independent risk factor affecting kidney function among middle-aged and older adults.

The research analysed data from 6,718 participants aged 45 years and above enrolled in the China Health and Retirement Longitudinal Study between 2011 and 2015. Researchers assessed kidney function using the estimated glomerular filtration rate (eGFR), a standard measure used to evaluate how efficiently the kidneys filter waste from the blood.

The study defined heatwaves based on varying temperature thresholds and durations of two to four consecutive days.

Researchers found that higher-intensity and longer-lasting heatwaves were associated with an increased likelihood of developing chronic kidney disease, indicating a dose-response relationship where greater heat exposure corresponded to higher health risks.

Chronic kidney disease is a growing global concern

Chronic kidney disease has become one of the leading causes of illness and death worldwide.

According to global estimates, around 843.6 million people were living with CKD in 2017. Although deaths directly attributable to end-stage kidney disease have declined in recent years due to improvements in treatment, CKD continues to emerge as a major contributor to global mortality.

Health experts warn that climate change may further increase this burden by exposing larger populations to prolonged periods of extreme heat.

How heat affects the kidneys

Extreme heat causes excessive sweating, leading to significant fluid loss from the body.

When dehydration occurs, urine production decreases and minerals such as calcium and uric acid become more concentrated. These minerals can crystallise, increasing the risk of kidney stones and placing additional stress on the kidneys.

Reduced blood flow caused by dehydration can also impair the kidneys’ ability to filter waste effectively, particularly during prolonged heat exposure.

Researchers observed that the adverse effects of heatwaves were more pronounced among people with pre-existing conditions such as hypertension, diabetes and heart disease, making these groups especially vulnerable.

Earlier research supports the findings

The latest findings are consistent with earlier research.

A 2022 study published in the American Journal of Kidney Diseases by the National Kidney Foundation (NKF) found that exposure to extreme heat was associated with an increase in kidney- emergency department visits.

The growing body of evidence suggests that rising temperatures linked to climate change are having measurable effects on kidney health across different populations.

Preventing heat- illness

The Ministry of Health and Family Welfare (MoHFW) states that heat- illnesses occur when the body is unable to cope with excessive heat.

These conditions include heat cramps, heat rash, heat exhaustion, fainting and heat stroke. Symptoms may initially appear mild but can worsen rapidly if left untreated.

Health experts recommend drinking adequate water, avoiding prolonged exposure to direct sunlight during peak afternoon hours, wearing light-coloured and loose-fitting clothing, taking frequent breaks while working outdoors and seeking medical attention if symptoms such as dizziness, confusion, severe fatigue or reduced urination occur.

While further research is needed to better understand the long-term impact of climate change on kidney health, experts agree that preventing dehydration and protecting vulnerable populations during heatwaves are important steps in reducing the risk of heat- kidney damage.