Even after 12 exhausting hours in the fields, farmworker Sudhakar Tasgave still struggles to get any rest. ‘I barely sleep for four hours,’ he says. Every morning, he feels drained and continues his demanding routine of spraying pesticides, followed by backbreaking tasks that include tilling, harvesting crops and hauling them in in the scorching heat of western India.
Initially, he ignored his insomnia, thinking it was temporary and would resolve itself within a few days. But when it became a pattern, he started to worry. ‘I kept wondering what was going wrong,’ he says. After monitoring his day for over a year, he realised that his sleep problems worsened after pesticide spraying.
Then the 55-year-old shared his observations with other farmworkers. Since then, he says, many have started noticing this pattern of disturbed sleep in their lives. This group of farmers from Yadrav village in India’s Maharashtra state isn’t alone in experiencing sleep issues associated with overexposure to pesticides.
Sometimes the pesticides get into my eyes and nose and cause many problems, but I’ve gotten used to it
Sudhakar Tasgave, farmerworker
Since 1990, global pesticide use has doubled, reaching 3.7 million tonnes in 2022. Globally, 873 million workers employed in agriculture are thought to be at risk from pesticides and agrochemicals, according to the International Labour Organization. And a growing body of research from around the world is uncovering strong links between pesticide exposure and disrupted sleep patterns. While earlier studies have linked pesticide exposure to adverse health effects, new research is uncovering how they disrupt human sleep patterns.
Exhausted, yet awake
Last year, a study of over 27,000 farmers in Thailand found that increased long-term pesticide exposure correlates with a higher risk of sleep disorders, demonstrating a dose–response relationship with 19 common pesticides.1
Many groups of pesticides like organophosphates, carbamates and pyrethroids can interfere with neurotransmitters
Chudchawal Juntarawijit, Naresuan University
Its lead author, Chudchawal Juntarawijit, an expert on pesticide toxicity at Naresuan University in Thailand, says pesticides can affect sleep in several ways. These include neurotoxic effects, where the brain and nerves are damaged by toxic substances. ‘Many groups of pesticides like organophosphates, carbamates and pyrethroids can interfere with neurotransmitters such as acetylcholine and gamma-aminobutyric acid, which regulate sleep by helping to slow down brain activity and prepare the body for rest,’ he explains.
As some pesticides are endocrine disruptors, a common pathway for this disruption is their impact on melatonin, the sleep hormone, and cortisol, a stress hormone, that work together to control the biological clock and sleep-wake cycle, he says.
A 2021 study, led by Astrid Zamora, a postdoc and epidemiologist at Stanford University school of medicine, investigated the association between urinary pesticide markers and household exposure and sleep health outcomes in a nationally representative sample of US adults.2 ‘The study revealed that specific classes of pesticides have a high structural similarity to melatonin and may interfere with the melatonin pathways, including the sleep/wake cycle,’ says Zamora. She notes that there is still a lack of human data on how pesticide exposure affects endogenous melatonin, naturally produced by the body, mainly by the pineal gland in the brain. However, animal studies have shown that carbaryl, a common insecticide, can alter pineal gland function and lower serum melatonin levels, which can disrupt sleep and shift its timing, she adds.
Another harmful effect of most pesticides, Juntarawijit says, is inflammation that causes redness, swelling and, sometimes, pain. ‘Pesticide exposure, especially over long periods, can increase brain inflammation, contributing to sleep fragmentation and poorer sleep quality,’ he adds. It may also increase inflammation in the nose and throat, thereby increasing the risk of sleep apnea, a condition in which breathing repeatedly stops and starts during sleep.
In Spain’s Almeria region, researchers reported in 2023 that pesticides disrupt sleep by altering the nervous system through mechanisms such as acetylcholinesterase inhibition, which leads to overactive nerve signalling and altered sleep patterns.3 They found that farmers in the area experienced greater sleep problems, including hypersomnia and insomnia, compared with non-farmers.
Similarly, a study of 253 Ugandan smallholders revealed that those who applied pesticides for up to two days in the past week had significantly higher odds of experiencing sleep problems, sleep inadequacy and snoring, compared with those who did not use any.4 The odds were even greater among farmers who applied pesticides on three or more days during the week. These farmers were about three times more likely to experience sleep problems, two and a half times more likely to feel they didn’t get enough sleep and four times more likely to snore.
Notably, they found that farmers who applied glyphosate, a widely used herbicide, during the week preceding the study visit, were more likely to experience sleep disturbance. In contrast, those who applied mancozeb, a commonly used fungicide, reported sleep issues regardless of whether they had used it in the past week or at any point in the previous year.
These findings are prompting concern. ‘There is a growing body of science connecting sleep disorders to pesticide exposure,’ says Sara Grantham, science, regulatory, and advocacy manager at Beyond Pesticides, a US-based nonprofit that advocates for a ‘world free of toxic pesticides’. She adds that research from around the world is discovering this association, particularly among farmers and farmworkers. ‘The current scientific literature is compelling in connecting pesticides to impacts on sleep, but warrants further research as it is understudied.’
Learning from others’ mistakes
Tasgave says he has spent over two decades spraying pesticides. ‘No one in the village must have sprayed as much as I have. I’ve used every kind of pesticide available in the market,’ he says, proudly calling himself a walking encyclopaedia of pesticides.
‘I’m one of the few farmers in the village who’s willing to spray any kind of pesticide, so others always rely on me for this,’ he says. On average, he sprays for about 25 days a month, working at least seven hours a day, all without any protective gear for INR800 (£6.90) per day. ‘It’s tough work. Sometimes the pesticides get into my eyes and nose and cause many problems, but I’ve gotten used to it,’ he adds.
Speaking about how potent some pesticides are, he says: ‘There are a few that leave a stench on your body that doesn’t go away even after two days. No matter how much you bathe, the smell remains.’ Over time, enduring this became a mark of strength in the village. ‘If you can spray these pesticides, you’re considered strong,’ he says.
However, this has come with a tremendous cost as Tasgave struggles to sleep at night, which he worries can lead to a lifetime of illness.
Dilip Shinde, a farmer from Maharashtra’s Jambhali village, has been spraying pesticides for over five years now. While Shinde also sprays pesticides for at least six hours a day, he says he remains wary of these agrochemicals and doesn’t do this work daily. ‘I’ve learned from other farmers’ experiences and stay extremely cautious, especially after seeing so many of them struggle with sleeplessness.’
It took Shinde three years to understand the long-term effects of the pesticides he uses. Last year, he lost a friend in the village to acute pesticide poisoning. ‘I know another farmworker who can’t walk anymore because of overexposure to pesticides,’ he says.
Shinde says he wears a mask when spraying highly toxic pesticides. ‘I also wash my hands several times after work. Many farmers don’t because pesticide exposure has just become a normal part of their daily lives,’ he says.
Change needed
In their study, the Spanish researchers found that farmers who used pesticides without wearing gloves were over three times more likely to experience insomnia than those who wore them. Similarly, not wearing a mask doubled the risk. The study highlighted that farmers who use personal protective equipment (PPE) face a significant reduction in their exposure levels and health problems.
Juntarawijit says that PPE should be mandatory for farmers spraying pesticides and calls for governments everywhere to regulate the use of highly toxic pesticides. He also advocates for adopting organic farming and integrated pest management practices that combine biological, cultural and mechanical methods to control pests, along with other low-pesticide farming techniques.
Farmers like 79-year-old Narayan Gaikwad from Jambhali highlight better pesticide practices are urgently needed. For 25 years, he sprayed pesticides without gloves or a mask until a doctor advised him to stop. The exposure caused nail dystrophy, leaving his nails brittle and full of pits. ‘I couldn’t sleep either,’ he told his doctor, who told him that the problem was overexposure to pesticides. Since then, he has become an advocate for pesticide-free farming, educating farmers in nearby villages about them.
A lack of awareness about working with pesticides is a challenge many people face. ‘Many unlettered farmworkers like me can’t read the instructions written on the bottles of pesticides,’ Shinde says. While he remains extremely cautious, he says he sometimes has health problems, which he links to pesticides. ‘Sometimes, I find it difficult to sleep, which affects my work the next day.’
Shinde is aware of the risks posed by pesticides, but he says it’s the only way he can make ends meet. ‘Once I get older, I know these pesticides will have an impact on my health, but at this stage, I can’t afford not to do this work.’ Tasgave also faces a similar dilemma. ‘If I don’t spray pesticides, I won’t be able to make a living. If I do, I will die from their harmful effects,’ he says.
Many farmworkers live with this silent trade-off, caught between survival and self-harm. When Tasgave wakes up in the middle of the night, he regrets his decision to work in the fields. ‘Every day, I tell myself I’ll quit this work, but that never happens,’ he says, his eyes fixed on the pesticide sprayer beside him.