Occupational heat exposure and sex- and gender-related vulnerability among women workers: a systematic review

The sun beats down on a field, and the air grows heavy with heat. For anyone working outdoors, this is more than just an uncomfortable feeling; it is a physical burden that the body must constantly fight. When a person works, their muscles generate their own internal warmth, adding to the heat coming from the sky and the ground. If the body cannot cool itself fast enough, it begins to struggle. This struggle, known as heat stress, can lead to dizziness, exhaustion, and damage to vital organs like the kidneys. While this danger is real for everyone, a critical question has long lingered in the world of public health: does the risk look different for women? For decades, scientists have debated whether women are biologically more fragile in the heat or if the danger comes from the way work is organized, the tasks assigned, and the social rules that govern who gets to rest and who must keep going.

A new systematic review, a type of study that gathers and examines many other research papers to find the bigger picture, has now tackled this question by looking at evidence from 2018 through 2026. The researchers focused specifically on women working in informal, precarious, rural, and agricultural settings—places where jobs are often unstable, protections are scarce, and the work is physically demanding. They analyzed 85 different studies from around the world, ranging from the fields of North America to the farms of Africa and Asia. Their goal was not just to count how many women got sick, but to understand how their biology, their social roles, and their working conditions mix together to create vulnerability. The findings reveal a story that is far more complex than a simple biological rule, pointing instead to a web of factors that determine who suffers and who survives the heat.

The researchers began by sorting through hundreds of reports to find those that actually measured heat exposure linked to specific jobs and included women. They found that the vast majority of the evidence came from agricultural work, with 74 of the 85 studies focusing on farmers, harvesters, and rural laborers. The studies used a variety of methods to understand the problem. Some relied on workers describing how hot they felt, while others used scientific instruments to measure the temperature, humidity, and radiation in the air. Some studies tracked the workers' heart rates and body temperatures, while others looked at blood and urine samples to see if their kidneys were under stress. The team also paid close attention to how each study treated the concepts of sex and gender. They distinguished between sex, which refers to biological traits, and gender, which refers to social roles, responsibilities, and the power to make decisions at work.

The results paint a clear picture of what happens when women work in the heat. The evidence consistently shows that exposure to high temperatures leads to a range of negative health outcomes. Women in these studies reported more frequent heat-related symptoms, such as dizziness and nausea, and showed signs of physiological strain, meaning their bodies were working harder to stay cool. A significant number of studies found that heat exposure is linked to dehydration and damage to kidney function. In some groups of agricultural workers, a large portion reached dangerously high body temperatures during a single shift, and others showed signs of acute kidney injury. The review also found that heat reduces a worker's ability to do their job, often forcing them to slow down or stop, which can threaten their income. For pregnant women, the heat poses specific risks, with studies showing changes in fetal heart rate and blood flow, suggesting that the stress of the heat reaches the unborn child.

However, the most important finding of this review is what it says about the cause of these problems. The evidence does not support the idea that women are universally biologically more susceptible to heat than men. The researchers found that when studies looked closely at the details, the differences in health outcomes were not explained by biology alone. Instead, vulnerability is shaped by how work is organized and the social conditions surrounding the worker. Factors such as the type of task a woman is assigned, whether she is paid by the piece which pressures her to keep working without rest, her lack of authority to stop work when she feels sick, and her responsibility for caring for children or family members all play a major role. These social and economic pressures often prevent women from accessing water, shade, or the ability to take a break, even when those things are technically available. The review highlights that a woman's risk is often higher not because her body is weaker, but because her job and her life leave her with fewer options to protect herself.

The researchers also looked at what can be done to prevent these harms. The studies they reviewed showed that the most common solutions offered are simple ones: providing water, training workers on the risks, and adjusting work schedules. While these measures are helpful, the review suggests they are not enough on their own. The authors argue that true protection requires a deeper change in how work is structured. This includes reducing the physical intensity of the work, providing engineering controls like shade or cooling systems, and ensuring that workers have the social and economic freedom to rest without losing their wages. The review notes that in many of the settings studied, a worker who stops to rest might lose their income or their job, making the advice to "take a break" impossible to follow.

Ultimately, this comprehensive look at the data tells us that heat vulnerability is not a fixed trait of a person's body but a result of the interaction between the environment, the work itself, and the social world. The evidence confirms that heat causes real harm to women in these jobs, damaging their kidneys, draining their energy, and threatening their reproductive health. But it also clarifies that the solution lies not in treating women as biologically fragile, but in fixing the systems that make them vulnerable. By addressing the conditions of work, the distribution of power, and the access to resources, it is possible to reduce the danger. The review concludes that protecting women from occupational heat requires a mix of better technology, fairer work policies, and a recognition that the ability to stay safe is often a matter of choice and opportunity, not just biology.