Silent dehydration is a condition in which the body gradually loses water and essential electrolytes without triggering the usual thirst signals. Unlike acute dehydration—which manifests through symptoms like dizziness, dry mouth, excessive thirst, and dark yellow urine—silent dehydration creeps in subtly, often going unnoticed until it causes severe health complications or even death.
The Rising Threat in a Warming World
In 2024, the Indian Medical Academy (for Preventive Health) hosted a seminar in Visakhapatnam titled “Understanding Silent Dehydration and Its Management.” With growing concerns over global warming and rising greenhouse gas emissions, scientists have warned that cities like Visakhapatnam in Andhra Pradesh are likely to face prolonged heat waves in the coming years.
Medical professionals at the seminar highlighted that these intense heat conditions are causing silent dehydration, particularly among children and the elderly. Referencing data from the India Meteorological Department (IMD), they noted that over 1,788 people in Andhra Pradesh have died due to heat-related causes in the past decade. Many of these deaths were likely connected to silent dehydration—an issue largely overlooked by both government and public health systems. The result: a growing influx of heat-affected patients in public hospitals.
“Many underestimate the dangers of heat. Having experienced many summers, they assume they’re immune to it. But heat can lead to rapid and fatal consequences,”
says Dr. Shailaja Tetali, Professor & Dean of Research & Policy Support at the Indian Institute of Public Health–Hyderabad.
She notes that there is no universally accepted definition for heat-related illnesses, which can lead to frequent misdiagnosis and underreporting. Compensation concerns may also contribute to the underreporting of heat-induced deaths.
The Heat–Kidney Disease Connection
A study based on data from the Longitudinal Aging Study of India (LASI) and weather information from the National Oceanic and Atmospheric Administration (NOAA) highlights the wide-ranging health consequences of heat, especially among the elderly across ten Indian states. These include not only physical illnesses like diabetes, asthma, and infectious diseases but also mental health issues like depression, fatigue, and anxiety.
The report underscores the importance of cooling infrastructure in rural areas and the availability of drinking water in urban workplaces. Environmentally conscious housing and favorable microclimates could be key in mitigating the impact of extreme temperatures. Despite these findings, comprehensive research on dehydration and its wider health effects remains lacking—especially among laborers and those working in open environments.
According to a recent International Labour Organization (ILO) report, 2.41 billion workers globally are exposed to extreme heat, leading to around 19,000 deaths annually—though it’s unclear how many of these are due to dehydration.
(https://www.ilo.org/publications/ensuring-safety-and-health-work-changing-climate )
In India, an estimated 380 million people—about 75% of the workforce—are employed in occupations that require direct exposure to sunlight. The consequences are dire: heat exposure affects the brain, heart, kidneys, lungs, liver, and intestines. Heat-related complications can persist even after the body temperature returns to normal.
Governments in several countries, including India, have announced changes to work hours during summer. However, implementation remains weak. In El Salvador, for example, studies show that up to 25% of the population in the Bajo Lempa region suffer from chronic kidney disease, attributed largely to dehydration. Kidney failure is now the leading cause of death among adults there. El Salvador’s story is a warning that resonates globally, especially in countries where outdoor labor under extreme heat is common.
Elderly at Highest Risk
The elderly are especially vulnerable to heat-related illnesses. According to Climate Central, more than 80% of the 12,000 heat-related deaths in the U.S. each year involve individuals over the age of 60. As people age, their bodies retain more heat, produce less sweat, and circulate blood less efficiently—making it harder to regulate body temperature.
The World Health Organization estimates that by 2050, the global population of those aged 60 or older will double to 2.1 billion. Already, people over 65 are experiencing 9.3 more heatwaves annually than they did in 1986–2005, leading to a 167% increase in heat-related deaths compared to the 1990s. Without rising temperatures, this increase would have been only 65%.
The 2022 European heatwave caused thousands of deaths across 21 countries, disproportionately affecting the elderly and those with chronic illnesses. In Spain and Portugal, the majority of victims were over 65.
(https://www.hrw.org/news/2022/08/12/europe-heatwaves-disastrous-older-people-people-disabilities )
What Can the Public Do?
“As a country deeply affected by climate change, India must urgently respond to the health risks posed by extreme temperatures. Children and the elderly are particularly susceptible to silent dehydration, as they have lower water and electrolyte reserves. Adults often mistake fatigue for age-related tiredness, while children may struggle to express discomfort. Many laborers bring their children to work under the scorching sun, without proper access to food, water, or shade. Those living alone may neglect their fluid intake, unaware that their bodies are deteriorating silently.” says Dr. V. Ramana Dhara, Fellow at the American College of Occupational and Environmental Medicine.
To adapt to the changing climate, both personal habits and public infrastructure must evolve. Experts recommend:
Avoiding outdoor activity during peak heat hours
Spending 2–3 hours daily in cool or shaded areas
Staying hydrated with electrolyte-rich fluids
Heeding official heat warnings
Never swimming alone or unsupervised
Dr. Tripathi of the Indian Medical Academy emphasizes the importance of Oral Rehydration Salts (ORS) in treating dehydration during diarrheal illnesses, and the use of homemade electrolyte drinks in non-diarrheal contexts. Community-level education, Dr. Rama Naidu adds, is essential to spreading awareness about silent dehydration.
Climate, Caste, and Health
India’s vulnerability to heatwaves is compounded by deep-seated social structures. A significant share of the population continues to work in caste-based, outdoor occupations—exposing them disproportionately to climate-related health risks. Addressing silent dehydration and heat-related illnesses thus requires not only medical and environmental interventions, but also a critical understanding of how caste, labor, and climate intersect.
Stronger legal safeguards for laborers, enforceable restrictions on outdoor work during heatwaves, and financial support during job disruptions are essential. Only through such comprehensive measures—grounded in science, equity, and compassion—can the silent crisis of dehydration be tackled before more lives are lost.
A.K. Shiburaj is an independent journalist and editor of Panthi.in
