Facing a phenomenon that affects a majority of workers at some point in their careers, France’s National Agency for Food, Environmental and Occupational Health & Safety (ANSES) is now calling for better protections for workers.
Atypical Schedules: Working Outside the Collective Rhythm Isn’t a Trivial Matter
In its expert review dedicated to atypical schedules other than night work, ANSES examines rhythms that have become commonplace across many jobs: starting at dawn, finishing in the evening, working weekends, or stacking long days. Indeed, the scale of the phenomenon is substantial: between 55% and 75% of workers in France would be affected by at least one form of atypical schedules during their professional life. Henri Bastos, ANSES’s Scientific Director for Health and Work, describes them as “far from marginal.” Yet behind this normalization lies a workplace health question: what happens when work hours persistently drift away from familiar biological and social rhythms?
Excluding night work, ANSES distinguishes three main situations. Long hours—days exceeding 8 hours or weeks exceeding 40 hours—fall into the category of long schedules. The agency also includes weekend work and shifted hours: from 5:00 a.m. to 8:00 a.m., then from 7:00 p.m. to midnight. This breakdown matters, because the observed effects are not identical from one rhythm to another. The ANSES assessment is based on 172 studies deemed relevant. They do not always allow a direct assertion that a given schedule causes a disease. ANSES therefore speaks cautiously of statistical associations, stronger or weaker depending on the circumstances. Workload, stress, sleep duration, sleep quality, and the overall organization of daily life can modify the observed effects.
A central concern, however, centers on a mechanism: desynchronization. Our everyday environment remains largely structured around relatively conventional collective rhythms. Children go to school during the day, services operate largely at set hours, families gather in the evening, and social activities often cluster in the evenings or on weekends. A person whose work runs counter to these rhythms thus has fewer opportunities to recover, to see loved ones, or to organize daily life in a normal way.
Alongside social desynchronization lie biological mechanisms. Atypical hours can disrupt the circadian clock, which helps regulate sleep and stress. Starting a job very early can shorten the night. Ending late shifts delays the time when the body can truly unwind. When these constraints recur, recovery becomes harder.
Atypical Schedules: Weekends and Long Days—The Risks Mount
Long days stand out as one of the best-documented aspects of the assessment. For this type of arrangement, the adverse effects on anxiety, sleep, and the incidence of cardiovascular disease are considered established by ANSES. In other words, the scientific signal is strong enough for the agency to distinguish these effects from associations still labeled as probable.
Other consequences exist but are less definitively established, yet sufficiently documented to warrant attention. Probable negative effects are noted regarding reproductive and metabolic health, the risk of depression, workplace accidents, and difficulty maintaining a satisfactory balance between work, family life, and social life. The issue is not merely fatigue at the end of a long day. It is the accumulation of constraints and the shrinking opportunities for recovery that concern the experts.
Weekends pose a different problem. Working when most family members, friends, or close ones are available can gradually reduce shared time. This social dimension is not separate from health. The studies reviewed by ANSES link weekend work to sleep disturbances, fatigue, pain, musculoskeletal disorders, and accidents, but also to mental health issues such as anxiety or depression.
From Night Work to Shifting Schedules: Why the Body Recovers Less
Night work already operates within a specific framework, and its health effects have been the subject of extensive research. ANSES now suggests paying closer attention to what happens at the edges of night: starting at 5 a.m., for example, or finishing at 10 or 11 p.m. These hours do not necessarily meet the legal definition of night work, but they can nonetheless strongly disrupt rest cycles and social activities.
Early-morning roles are particularly associated in the analyzed studies with effects on sleep, mental health, and cardiovascular health. Waking several hours before the rest of the household often forces an earlier bedtime, which isn’t always possible when family constraints persist in the evening. Sleep debt can then accumulate. And insufficient recovery isn’t limited to sleepiness: it also interferes with stress levels and the body’s overall functioning.
Evening schedules more directly affect the socio-familial sphere. Finishing when children are going to bed, only crossing paths with a partner, or being unavailable when friends meet can trigger a form of ongoing misalignment with one’s environment. Access to certain services, such as childcare or transportation, can also be reduced.
This reality explains why ANSES emphasizes the cumulative nature of exposures. A person might work early shifts for a few years, then move to long days, then regularly work weekends. Each arrangement may not have the same impact, but a career can stack different constraints. For the agency, prevention must therefore consider not only the current schedule but also exposure over the long term.
Shifting Schedules: What ANSES Recommends to Better Protect Employees
The agency’s primary message is simple: regular use of atypical schedules should be “limited as much as possible.” This isn’t about denying the needs of hospitals, transportation, security, industry, retail, or many services. Some roles require particular ranges of hours. The challenge is to prevent these arrangements from becoming a default solution when their necessity isn’t clearly established. When these hours cannot be eliminated, ANSES wants them better prepared and governed. The organization should be “transparent, predictable and balanced.” Predictability is essential: knowing your schedule well in advance gives more opportunities to organize sleep, family obligations, childcare, transportation, or personal appointments.
The agency also recommends not concentrating the constraints on the same people. In services requiring continuous operation, it suggests distributing exposure more evenly, considering personal preferences and constraints, and tracking actual schedules over the course of a career.
The other strong avenue is to bring protection for these workers closer to what is already in place for night work. ANSES mentions, in particular, tailored medical monitoring and special provisions for pregnant workers. It also highlights accommodations that directly support recovery rather than providing a solely financial response: reduced working time while maintaining pay, compensatory rest, help with transportation or childcare.
Read also
Practical nutrition case: I work at night. How to eat well
Night work could affect women’s fertility
