Climate change is often discussed through the language of disasters. We tend to recognise its impacts through images of flooded villages, eroded riverbanks, destroyed homes and economic losses. In Bangladesh, public debates and policy responses are largely shaped by cyclones, floods and other visible climate-related events that demand immediate action. Yet another climate crisis is unfolding every day in Bangladesh's cities, one that rarely makes headlines. It does not leave behind collapsed buildings, washed-away roads or dramatic scenes for television cameras. Instead, it works silently and relentlessly, taking a toll on people's bodies, health and livelihoods. This crisis is heat stress.

Across Dhaka and other urban centres, rising temperatures are imposing a growing physiological burden on millions of informal workers and low-income urban residents. Climate change is no longer only reshaping landscapes and livelihoods; it is increasingly altering the body's ability to work, rest, recover and survive. Meteorological data also confirms what workers have been experiencing for years. The World Bank also acknowledges that Bangladesh now ranks second globally in exposure to extreme temperatures, and Dhaka's heat index has risen to about 65 percent above the national average. Behind these statistics are real people whose bodies absorb the hidden costs of climate change every single day.

For rickshaw pullers, there is no fixed workplace, regulated break or guaranteed access to drinking water. Many drink only when water is available, increasing the risk of chronic dehydration and long-term health problems. Photo: Amran Hossain

This reality emerged clearly from two studies conducted by the Ovibashi Karmi Unnayan Program (OKUP) in 2025 among informal workers and internal migrant communities living in Dhaka's informal settlements. The findings reveal that extreme heat is not simply causing discomfort. It is undermining physical health, worsening mental well being, reducing productivity, increasing healthcare costs and deepening existing social inequalities.

The findings challenge a common misconception that heat is merely a seasonal inconvenience. For many (81%) informal workers, heat has become a constant threat that follows them from their homes to their workplaces. Most informal workers live in densely populated slums where housing is constructed from corrugated tin sheets, ventilation is poor and access to cooling is limited. During heatwaves, these small rooms trap heat throughout the day and release it slowly at night, turning homes into ovens. Water becomes too warm to drink or bathe, food spoils quickly and sleep becomes nearly impossible, taking a severe toll on both physical and mental health and diminishing people's ability to work and earn.

During an interview conducted by OKUP, an informal worker from Agargaon slum recalled the ordeal of living through the 2025 heatwave. He said, "Last year (2025), during the peak of the heatwave, the temperature reached nearly 42°C. It felt impossible to breathe inside our house. The heat was so intense that I felt like I would turn into puffed rice if I stayed there any longer. I went outside looking for some relief, but the roads were just as hot. There was nowhere to escape. Inside the house was unbearable, and outside was no better. I felt like I was dying."

Approximately 76 percent of workers who participated in the research reported experiencing sleepless nights, chronic fatigue and persistent exhaustion during the summer months. Many (73%) reported waking repeatedly throughout the night due to heat and discomfort. The result is a dangerous cycle. Workers begin each day already fatigued. Their reduced physical resilience increases susceptibility to heat-related illnesses, which in turn further compromises recovery and productivity.

His experience is not an isolated case; it reflects a broader urban reality. For millions of informal workers, there is often no refuge from extreme heat. The home, which is usually expected to provide rest and help the body recover, instead becomes a source of thermal stress. This has profound physiological consequences. Sleep is one of the body's most important recovery mechanisms. It allows muscles to repair, hormones to regulate, immune systems to strengthen and cognitive functions to recover. Yet heat disrupts sleep patterns by preventing the body from achieving the temperature reductions necessary for restorative rest.

Approximately 76 percent of workers who participated in the research reported experiencing sleepless nights, chronic fatigue and persistent exhaustion during the summer months. Many (73%) reported waking repeatedly throughout the night due to heat and discomfort. The result is a dangerous cycle. Workers begin each day already fatigued. Their reduced physical resilience increases susceptibility to heat related illnesses, which in turn further compromises recovery and productivity. Workers also reported recurring fevers, gastric complications, respiratory problems, elevated blood pressure and increased vulnerability to illness during the summer months. While some of these conditions may appear unrelated to temperature, growing scientific evidence suggests that prolonged heat exposure contributes to a wide range of adverse health outcomes.

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Child labourers bear an especially heavy burden from extreme heat. Working long hours under Dhaka’s scorching sun, often while carrying heavy loads or performing physically demanding tasks, children face heightened risks of dehydration, exhaustion and heat-related illness, adding another layer of vulnerability to an already hazardous working life. Photo: Rashed Shumon

However, this burden does not end at home. Conditions are often even more severe in workplaces. Construction workers and day laborers endure long hours under direct sunlight, frequently in poorly ventilated or unsafe environments, with little or no protection during periods of extreme heat. OKUP’s research found that workers frequently experience muscle cramp, dehydration, fatigue, and in severe cases heatstroke. Rickshaw pullers face even greater exposure. without fixed workplaces, regulated breaks, or reliable access to drinking water, many drink only when water is freely available. Over time, this pattern increases chronic dehydration and contributes to long-term kidney and other health complications.

Garment workers face a different but equally severe form of risk. Many (81% of the surveyed RMG workers) work in Tier 3 factories located in residential buildings that are small, overcrowded and poorly ventilated, with low ceilings and heat-generating lights that intensify indoor temperatures. Production pressure further compounds the problem. Workers often reduce their water intake to avoid toilet breaks, which are discouraged under strict time targets and supervisory pressure. This leads to urinary tract infections, abdominal pain, dizziness and persistent fatigue, conditions that intensify during hotter months. What is most alarming is the normalisation of this suffering. Many garment workers come to view chronic headaches, dizziness, nausea and exhaustion as routine aspects of employment rather than warning signs of a deeper occupational health crisis. Over time, this normalisation obscures the cumulative strain placed on the body, particularly on the cardiovascular and renal systems.

Akram, a garment worker employed in the cutting section of a garment factory, described the reality of working under such conditions:

"The situation is worst in the cutting section where I work. Nearly 200 of us work together in a closed room. The heat from our bodies, the machines and the lights keeps building up throughout the day. It becomes very difficult to continue working, especially during the summer. When there is load shedding and the fans stop, the situation gets much worse. We feel exhausted, dizzy and short of breath. Last year, one of my colleagues died from heatstroke. After that, many of us became afraid because we know it could happen to us at any time."

Domestic workers experience additional layers of vulnerability. Domestic workers perform physically demanding tasks such as cooking, cleaning and climbing stairs under extreme heat. At home, they also carry a disproportionate burden of unpaid care work, which increases when heat related illness affects children, elderly relatives and other family members. This makes heat stress both an occupational and a gendered burden.

Beyond physical health, extreme heat erodes both mental well being and economic stability. Workers (79%) reported irritability, anxiety, emotional exhaustion and reduced concentration during periods of extreme heat. These experiences are closely tied to chronic fatigue, poor sleep quality, declining productivity and growing financial insecurity. Prolonged exposure to high temperatures not only weakens cognitive performance but also intensifies psychological distress, creating a feedback loop between physical exhaustion and mental strain.

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Heat does not stop the work. For many low-income workers, taking a break can mean losing part of their daily income, leaving them caught between protecting their health and keeping their livelihoods afloat. Photo: Firoz Ahmed

For workers who depend on daily wages, the consequences are immediate and severe. Missing work due to illness results in direct income loss, while taking breaks to avoid heat exposure can reduce already limited earnings needed for rent, food and healthcare. This creates an impossible dilemma: workers must choose between protecting their health and sustaining their livelihoods. Resting to recover means losing the day’s income, while continuing to work under dangerous conditions risks further deterioration of health and productivity.

Despite increasingly frequent heatwaves and evidence of their health impacts, heat remains largely absent from Bangladesh's labour regulations, public health surveillance systems and urban planning frameworks. While climate adaptation policies have focused heavily on floods, cyclones and physical infrastructure, far less attention has been paid to the physiological consequences of rising temperatures for workers.

As a result, workplace protections remain weak or absent. Informal workers lack access to shaded rest areas, cooling facilities, regulated breaks and heat specific safety standards. Public health systems rarely track heat related illness systematically, rendering its burden largely invisible in official statistics. In Dhaka, rapid concrete expansion continues to outpace green infrastructure, while heat sensitive planning remains limited.

Heat is no longer simply a meteorological condition measured in degrees Celsius. Its real cost is visible in the exhausted worker enduring long shifts under unbearable conditions, the sleepless household under a tin roof and the slow erosion of physical and mental health across urban communities. If climate change is entering the body, then adaptation must begin there too. When heat becomes bodily, it is no longer an abstract environmental challenge; it becomes a question of survival and justice.

If Bangladesh is serious about climate justice, it must move beyond viewing informal workers as passive victims of climate change and recognise them as citizens whose health, dignity and livelihoods deserve protection. Climate adaptation strategies cannot succeed if they overlook the people who experience the most intense and prolonged exposure to extreme heat. Urban planning, affordable housing initiatives, heat action plans and social protection programmes must explicitly address the needs of informal workers.

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For workers exposed to extreme heat, there is often little relief during the working day. Dehydration, fatigue and heat-related illnesses are common among construction workers, day labourers and other informal workers who spend long hours outdoors. Photo: Prabir Das

Practical interventions already exist. Community cooling centres, shaded public spaces, reflective and green roofing programmes in low income settlements, accessible drinking water points and enforceable occupational heat safety standards could significantly reduce workers' exposure and improve their ability to recover from heat stress. These measures are not luxuries; they are essential investments in public health, labour protection and climate resilience. Without such measures, Dhaka risks becoming a city where millions are forced to endure extreme heat without protection, with growing costs in health, productivity and well being.

If Bangladesh is to build genuine climate resilience, adaptation must begin with the human body. Climate change is not experienced only through floods, cyclones or rising temperatures recorded by weather stations. It is experienced through dehydration, sleepless nights, exhaustion, illness and lost livelihoods. When climate change enters the body, it ceases to be an abstract environmental challenge and becomes a matter of human survival.

Urmi Jahan Tanni is a Research Manager at Ovibashi Karmi Unnayan Program (OKUP).

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