When the Heat Steals Your Smile
- Zain Azhar, Earth Island Journal
- Jun 7
- 12 min read
Updated: Jun 9
A dentist documents how extreme heat is turning Pakistani farmworkers’ mouths into hostile environments for their own teeth.
This article originally appeared on Earth Island Journal. Subscribe to their newsletter here.
Rashid has calloused hands and the weathered face of a man who’s spent three decades under the Pakistani sun. What the 32-year-old doesn’t have anymore are functional teeth. Eight of them — gone in two years. The rest are deteriorating so rapidly that he’s already resigned himself to dentures by 40.
Rashid is a sugarcane farmer in Jhang District, Punjab province, where temperatures regularly exceed 45 degrees Celsius (113 degrees Fahrenheit) during peak summer months, transforming agricultural work into a form of biological endurance that few understand. Just last summer, the city of Jacobābād in Sindh province recorded 51°C — making it one of the hottest human-inhabited places on Earth and creating conditions that push human physiology to its absolute limits.
When I first examined Rashid in my Lahore clinic in early 2022, I noticed something that didn’t fit the typical decay pattern I’d seen in rural patients across six years of dental practice. This wasn’t the gradual erosion from poor hygiene or untreated cavities that you’d expect in communities with limited access to healthcare. This was aggressive, systematic dissolution — as if teeth were being chemically attacked from the inside out, dissolved by forces entirely beyond individual control or comprehension.
This was environmental collapse writing itself directly into human biological systems.
Like most outdoor laborers during peak season, Rashid drinks 15 to 20 liters of water daily to survive the relentless heat. By mid-morning, sweat soaks through his clothes as his body’s cooling mechanism works overtime. He chews on sugarcane during breaks, which provides quick calories — an ancient practice that sustained ancestors but now compounds health problems. Nothing about his general health seemed unusual at first. But when I asked about saliva — that often-overlooked component of oral health that most people never think about — there was a long pause.
“My mouth is always dry,” he said quietly in Urdu. “Even when I drink water until I feel sick. My mouth stays dry.”
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That’s when something clicked into place that would fundamentally reshape my understanding of what I’d been observing in my practice. I’d documented this pattern of tooth decay in 37 patients by this point, all agricultural workers, all from the same climate-ravaged zones in the central-eastern state of Punjab. I just hadn’t connected the dots to heat-induced dehydration and its catastrophic effects on oral chemistry. Their mouths weren’t just dry — external climate forces were fundamentally turning them into hostile environments for their own teeth. I realized I was witnessing something far more systemic and urgent than a collection of individual dental problems. This was environmental collapse writing itself directly into human biological systems.
Saliva is not just moisture. It’s a physiological fortress, a sophisticated system that most people take entirely for granted until it fails them. For anyone, but especially for people doing physically demanding work in extreme conditions, saliva performs three critical functions that are absolutely essential to tooth survival: It buffers acids from food and stomach reflux that would otherwise erode enamel; it holds calcium and phosphate minerals, which actively remineralize tooth enamel when microscopic damage occurs; and it contains enzymes and antibodies that fight bacteria, helping prevent infection and decay.
Without adequate saliva flow — and I mean genuinely adequate, not just the minimal amount needed to swallow — teeth begin to demineralize within weeks, a process that becomes increasingly difficult to reverse.
Heat stress triggers a biological cascade that is as predictable as it is brutal. When outdoor workers experience prolonged exposure to temperatures above 40°C day after day, their bodies are forced to prioritize cooling through perspiration over virtually every other function. This leads to fluid being diverted away from salivary glands and toward sweat production because the body’s survival calculus, the result of millions of years of evolutionary programming, is simple: prevent immediate heatstroke, worry about other problems later.
To understand the deeper physiological mechanism at play, I reached out to Abida Farooqi from Quaid-i-Azam University’s Department of Environmental Sciences. Farooqi, who has researched the health impacts of groundwater fluoride and arsenic contamination for over 20 years, confirmed what the data from my patients was suggesting.
“When a person is dehydrated, saliva production decreases, and the saliva becomes more concentrated [and acidic],” she wrote in an email response. “Reduced salivary flow decreases [salivary] bicarbonate [the primary buffer against oral acids], allowing oral pH to drop more easily,” she noted. “Acidic conditions are favorable for [cavities] and enamel demineralization, and reduced saliva also decreases antimicrobial activity.”
At 5.2 pH, enamel doesn’t just demineralize slowly; it actively dissolves, like chalk in vinegar.
Farooqi’s explanation of pH concentrations aligns with what I’d been observing. After I suspected a climate connection to tooth decay, I conducted systematic saliva pH testing across my patient population and documented pH readings below 5.5 in 42 of my 73 climate-exposed patients, primarily sugarcane workers, cotton pickers, and construction laborers from Punjab’s most heat-affected districts. (I’m using only their first names, or referring to them as “patient” to protect their privacy.) For instance, the mouth pH of one of the patients with severe tooth decay, a 28-year-old farmworker from Okara District, one of the hottest regions in Punjab, measured at 5.2 over multiple visits. Healthy saliva should maintain a pH closer to 7.0, neutral territory where minerals stay stable, and enamel remains protected. At 5.2 pH, enamel doesn’t just demineralize slowly; it actively dissolves, like chalk in vinegar, at a rate I’d never documented before.
In contrast, only three of my non-agricultural patients — people working indoors who are not generally exposed to extreme heat — showed similar readings. The difference was striking and clinically significant.
The rapid physiological damage to teeth among heat-exposed workers is visible and measurable. But because it’s a dental issue — because it doesn’t kill people quickly like heatstroke does — it’s been largely ignored by the medical establishment. That’s a profound oversight with serious consequences, particularly in a country like Pakistan, which is among the world’s most vulnerable to climate change.
Pakistan’s agricultural labor force — comprising about 27 million people — faces temperatures above 40°C for extended periods each summer, a warming trend that has worsened dramatically over the past three decades. During the catastrophic 2022 heat wave that made international headlines, outdoor workers in Punjab averaged heat exposure equivalent to standing in a 43°C environment for 12 or more hours daily, with minimal shade and limited access to drinking water. The physiological toll from this kind of exposure accumulates relentlessly, compounding daily, until the body begins to fail at cellular and systematic levels.
While devastating heat stress isn’t the only culprit behind dental deterioration. Climate-driven changes in groundwater quality and dietary shifts, too, are playing compounding roles.
Pakistan’s agricultural zones are experiencing a dramatic drop in groundwater due to reduced rainfall and higher rates of evaporation from freshwater bodies. This, in turn, concentrates dissolved salts in the groundwater, turning it more brackish during dry months. Regular consumption of brackish water — water with elevated salt content — creates an osmotic effect inside the mouth, pulling moisture out of oral tissues and worsening the dry-mouth conditions caused by heat stress. Beyond the mouth, prolonged consumption can burden the kidneys and irritate the digestive system.
When workers drink from these compromised sources during extreme heat, they’re consuming water that may already be either slightly acidic or mineral-poor. Combined with heat-induced salivary changes, this creates a knock-on effect.
Meanwhile, during the monsoons, when water is more abundant, chemicals — including nitrates and phosphates from agricultural and municipal sources — leach into the groundwater, which, Farooqi says, can lead to its acidification. Acidic water, or water with low pH, usually contains less dissolved minerals like fluoride and calcium, which are important for teeth health. “Fluoride, minerals, and pH affect each other,” Farooqi explains. “Higher pH and adequate calcium levels enhance fluoride’s ability to promote enamel remineralization, while low pH combined with low mineral content increases enamel demineralization and cavity risk.”
Increasingly erratic monsoons — along with land degradation and other issues — have also been impacting crop yields in Pakistan’s agricultural belt. (In 2025, the country’s output of major crops dropped by 13.5 percent.) Malnutrition among agricultural families has worsened significantly. According to data from Pakistan’s National Nutrition Survey, roughly 28.9 percent of children under five were underweight in 2018, and about 40.2 percent of children in the same age group were stunted. Agricultural wages for outdoor workers have stagnated while food prices have skyrocketed in recent years. Almost half of all rural agricultural families are now undernourished, struggling with food insecurity, and unable to provide adequate nutrition to their children.
One farmer described the economic reality with painful clarity: “Twenty years ago, we ate what we grew: wheat, vegetables, milk from our animals. Even in difficult years, we had this. Now I can’t afford that anymore. And I chew betel nut because it keeps me alert through the heat, keeps me working longer. My teeth pay the price for all of it. But what choice do I have?”
In recent years, many families have begun to consume packaged drinks high in sugar in lieu of drinking water because they feel like a sealed factory-made drink is safer (and tastier) than brackish tap water. There is a clear psychological dynamic playing here: Paying for bottled water feels irrational when tap water has always been free, but spending on a soda feels like a small, justified treat.
Many farmers were already eating sugarcane or jaggery as a caloric supplement during long work days — a practice that made sense nutritionally but made their mouth environment acidic. Now, their diets are increasingly dominated by cheap soft drinks and packaged snacks, which also tend to be acidic. So you have a perfect storm of acidic food meeting demineralized teeth meeting chronic dehydration meeting heat stress.
My research that when workers in their late twenties and early thirties lose functional teeth, they don’t just lose the ability to chew solid food, though that’s devastating enough. They are fundamentally unable to do their jobs effectively. Agricultural and other manual labor is physically demanding, and, since tooth loss makes it hard for them to eat properly during long work days, their energy levels drop. Physical endurance diminishes. Productivity decreases significantly. Wages drop accordingly.
Additionally, there’s a stigma associated with having bad or no teeth. One of my patients, a 26-year-old construction worker in Faisalabad, who has lost four front teeth and has six others that are showing severe decay, described it this way: “Contractors see you and assume you’re weak, unreliable, physically breaking down. I lost three job opportunities after they saw my teeth. They literally told me they couldn’t hire someone who looked that ill.” He’s now unemployed, living with his parents at an age when he should be establishing his independence. “My friends joke that I look like I’m 60,” he said, with the weariness of someone who’s heard that comment one too many times.
“I lost three job opportunities after they saw my teeth. They literally told me they couldn’t hire someone who looked that ill.”
Nasreen, another patient from Lahore, who used to work in construction but shifted to domestic work as her tooth loss progressed, says her condition, which has affected her speech (the loss of front teeth disrupts the ability to pronounce labiodental sounds like “f” and “v”), is costing her domestic work opportunities as well. Households hiring for in-home roles have turned her away, telling her she appeared “unclean.” Nasreen told me she stopped going to the market — the central gathering place for her community. “People stare,” she said. “In my community, a woman without teeth is considered unmarriageable. It’s not stated explicitly, but everyone knows it. My younger sister’s marriage prospects are affected too, because people talk. They wonder if there’s something genetically wrong with our family.” Nasreen used to earn 800 Pakistani rupees (about $2.85) a day as a construction worker; now she makes 400 rupees (roughly $1.45) a day, a 50-percent reduction that her family can barely absorb.
The broader economic dimension of this crisis extends far beyond individual persons or households. Farhan Ali Virk, assistant professor of economics at Government College University Lahore, framed it in terms of systemic economic collapse: “Climate change not only reduces crop yields; it also erodes the biological capacity of the workers who sustain agricultural production. When heat stress, dehydration, and nutrition insecurity accelerate health problems — such as dental erosion among outdoor laborers — the result is a hidden productivity shock that compounds rural poverty and wage stagnation. In economies like Pakistan’s, where agricultural workers already lack social protection, climate-induced health deterioration can push vulnerable households into deeper economic marginalization and intergenerational poverty.”
When a 28-year-old loses the ability to eat, speak clearly, smile, and work because of a climate crisis created primarily by high-emission countries on the other side of the world, that’s not just a dental issue, it’s a manifestation of environmental racism and climate apartheid. And it demands urgent recognition and immediate response.
In 2022, the Pakistani government formally declared climate change a national security priority. It has launched various initiatives to address the crisis — such as a national clean air policy, a transport and energy sector decarbonization strategy, and a national flood protection plan. Yet the country has virtually no plan in place to address its public health consequences. This gap in institutional attention reveals a troubling oversight in how climate adaptation is conceptualized as solely an infrastructure and economics problem. The result is a public health crisis unfolding in hard-hit rural communities that is receiving scant institutional recognition.
What gives me genuine hope amid this, however, are the community responses emerging organically without government support.
In 2023, in the Punjab village of Chak Beli Khan, for instance, a local health worker named Shabana Khan started organizing work shifts that avoided peak heat hours — a simple intervention based on understanding that the worst heat occurs between 11 a.m. and 4 p.m. Shifting work hours from the traditional 6 a.m. to 2 p.m. schedule to 4 p.m. to midnight helped farmworkers reduce their peak heat exposure significantly. Crucially, it also improved their hydration capacity; workers can actually retain fluids better when working in cooler hours, when their bodies aren’t in constant crisis mode trying to cool down.
I’ve documented the results of this intervention over a period of two years: Two workers reported improved oral health six months in. More significantly, their saliva pH readings improved from an average of 5.1 — dangerously acidic — to 6.2, moving into healthier territory. Word spread through the region. By the following harvest season, eight surrounding villages had adopted similar work schedules. It’s not a perfect solution — the work remains physically demanding, and wages haven’t increased — but it’s a real improvement from their previous work situation, and it emerged from on-the-ground wisdom.
Even these emerging solutions are, in truth, band-aids applied to a systemic wound that requires major intervention.
Similarly, in Faisalabad, a local microfinance and community health organization operating with limited resources began providing subsidized water stations and electrolyte solutions to agricultural laborers during harvest season to help their bodies retain fluids and maintain proper chemistry. It has made a measurable difference.
One patient told me, “My mouth felt different within weeks — less dry, less burning sensation, like my mouth was actually producing moisture again.” His saliva test showed improved chemistry across multiple markers. After I documented results in 15 workers there and helped the organization understand the clinical significance of what they were observing, the organization began lobbying provincial agricultural authorities to fund the work as an official worker-safety program. The group is now building the case for funding by compiling clinical evidence and lived testimony.
In Lahore’s climate research community, preliminary research on heat-driven oral health impacts represents an entirely new frontier — an area that has been virtually unstudied until now. But early conversations among researchers indicate a genuine interest in documenting and scaling this research to other regions of Pakistan and eventually to other countries in the Global South that are facing similar conditions.
But even these emerging solutions are, in truth, band-aids applied to a systemic wound that requires major intervention, both nationally and at the global level. What’s genuinely needed is policy change on multiple fronts: government-supported mobile dental clinics in agricultural zones with expertise specific to climate-related oral disease; binding workplace regulations for shade structures and mandatory hydration protocols during extreme heat; food-security programs that support truly nutritious food access in rural communities and don’t depend on cheap, processed foods; targeted health insurance, specifically for agricultural and other outdoor workers, covering both preventive and restorative dental care; and finally, climate-adaptation planning that centers human biology and human dignity, not just infrastructure and economic metrics.
Rashid came back to my clinic recently, his face showing the toll of another harvest season. We discussed implants as a long-term solution, knowing full well that he cannot afford them — the cost is prohibitive for an agricultural laborer earning 400 to 500 rupees a day. Before he left my clinic that day, I asked him what he’d want people to know about what’s happening to him and others like him.
“Tell them that climate change isn’t abstract,” he said. “It’s here, right now, in my mouth, in my family’s survival, in my ability to work and eat and live with dignity… It’s not just teeth; it’s my entire future. And I’m not alone. Every farmer I know is experiencing this. We’re all getting older before our time. We’re all becoming invisible.”
