Why Night Work Is Driving New Labor and Health Scrutiny

Health risks linked to night work and rotating shifts are drawing increased attention in Mexico as lawmakers, regulators and employers reassess labor practices ahead of broader reforms set to take effect in 2026.

“Working at night goes against the entire circadian system of the human body,” said Dr. Fructuoso Ayala Guerrero, UNAM Faculty of Psychology, during the 2nd International Congress of Work Psychology, noting that biological disruption affects physical, mental and cognitive performance.

Night work and rotating shifts remain common across sectors such as health care, transportation, manufacturing and security, supporting continuous operations but placing strain on workers’ health. Scientific evidence presented by UNAM explained that human physiology evolved around a 24-hour light-dark cycle regulated by the suprachiasmatic nucleus in the brain, which coordinates sleep, hormone release, alertness and energy use. Exposure to light at night and inverted work schedules disrupt this internal clock, altering the release of cortisol and melatonin, hormones essential for wakefulness and rest.

According to Ayala Guerrero, disrupted sleep affects more than rest. Sleep is an active biological process tied to tissue repair, memory consolidation, emotional regulation and metabolic balance. Interrupted or insufficient sleep, common among night and shift workers, has cumulative effects that include irritability, reduced concentration, fatigue and higher risks of cardiovascular and metabolic disease. Accident risk also rises sharply during early morning hours, particularly between 1 a.m. and 4 a.m., when alertness and reaction times decline.

These findings align with international data. The World Sleep Society estimates that 35% of people do not get sufficient sleep, while Mexico’s Ministry of Health reports that roughly 45% of adults experience poor sleep quality. Fatigue has direct implications for productivity and safety. “When someone fatigued performs complex or dangerous work, there is a high accident rate and productivity remains low,” said Rafael Echavarría, President and CEO, Fatigue Science, citing risks in transportation and mining.

Health concerns tied to night work are increasingly intersecting with policy discussions. In January, a constitutional reform proposal was introduced by Ricardo Madrid, Deputy, PVEM, to explicitly prohibit hazardous, unhealthy and night work for people under 18. The initiative would limit work hours for minors to six hours per day, ban overtime and reinforce the prohibition on employment under age 15. Supporters argue the reform addresses physical, mental and social development risks associated with early exposure to night work, particularly amid rising child labor linked to poverty and economic shocks.

Official data underscores the scale of the issue. In 2022, Mexico had 3.7 million children engaged in child labor, according to the ENTI survey. Nearly 57% were involved in work not permitted by law, including hazardous tasks and late-night shifts. Over half of these minors worked in dangerous conditions as defined by the Federal Labor Law, with agriculture, services and commerce among the most affected sectors.

Night and irregular shifts also carry gender dimensions. The International Labour Organization (ILO) reports that women are more likely to experience stress, anxiety and work-related mental health issues, while men face higher rates of severe accidents. Women are overrepresented in sectors with irregular schedules, such as caregiving and services, and often shoulder unpaid domestic work alongside paid employment. The ILO notes that personal protective equipment and risk assessments frequently fail to account for anatomical and social differences, reducing effectiveness and increasing exposure.

At the same time, employers are testing alternatives. Chronoworking, a model that aligns work schedules with individual circadian rhythms, is gaining attention as companies reassess rigid schedules. The approach promotes flexibility by matching tasks to periods of peak alertness, a concept supported by research linking circadian alignment to improved cognitive function and reduced fatigue. Advocates argue that while not feasible for all industries, greater flexibility could mitigate health risks in knowledge-based and hybrid roles.

Regulatory momentum is reinforcing this shift toward occupational health. Mexico fully enforced the Ley Silla in December, requiring employers to formalize rest breaks and provide seating with backrests for workers who perform standing tasks. Authorities frame the reform as a preventive health measure, citing evidence linking prolonged standing to musculoskeletal and circulatory conditions. Inspectors may now request proof that internal regulations include rest and seating provisions, with fines assessed per affected worker.

The focus on fatigue, rest and health is part of a broader labor overhaul. Entering 2026, employers have higher minimum wages, mandatory social security enrollment for digital platform workers, stricter payroll oversight and preparation for a gradual reduction of the workweek to 40 hours. Officials argue that these measures, combined with the enforcement of existing health protections, can reduce accidents and absenteeism while supporting productivity.

For businesses, the challenge lies in balancing compliance with operational demands. Experts note that night work will remain unavoidable in many sectors, but managing its impact is increasingly viewed as a risk and productivity issue rather than a scheduling preference