Carlos O. N. is 44 years old and works for the Madrid Metro. He’s been pulling the night shift for 10 years. Before that, he worked the evening shift for five years, finishing at 2 a.m. He tells EL PAÍS that he sleeps between five and six hours a day. However, he clarifies that reaching six is pretty exceptional.
“Anyway, I have the feeling that it doesn’t matter how many hours you sleep, because they’re never as restorative,” he sighs. “Sleeping during the day doesn’t produce the same quality of rest as sleeping at night.”
At work, he explains, it’s common for colleagues on the night shift to chat about the amount of sleep they get. As a general rule, they tend to only get a few low-quality hours. “You go against the normal life of society,” Carlos adds. “And, if you want to adapt to it, you end up feeling sleepy; you drag along a sleep deficit that takes its toll on your body. Over the years, I’ve noticed a fairly significant deterioration.”
“Capitalism is killing us with sleep,” says Juan Antonio Madrid, a professor of Physiology and director of the Chronobiology and Sleep Laboratory at the University of Murcia in Spain. During an interview with EL PAÍS, the expert laments that our society is plagued by “chronodisruption,” in which excessive light at night, long shifts, sedentary lifestyles, screen usage before going to sleep and distorted work and leisure schedules encourage a sustained, long-term alteration of biological rhythms. This ultimately translates into an alteration of sleep rhythms.
In his reflection, Madrid repeatedly refers to the impact that work schedules have on sleep.
According to the results of a recent study, non-standard work schedules — namely shift work, especially at night — together with sedentary jobs, are two of the most important threats to sleep health.
Specifically, non-standard shift work schedules correlate with a 66% higher risk of employees needing to “catch-up on sleep,” which is defined as frequent naps, or sleeping in on weekends. “The way we design work can pose serious, long-term threats to healthy sleep, which involves more than just getting eight hours. It also involves falling asleep easily, sleeping through the night and having a consistent sleep schedule,” says psychologist Claire Smith, a researcher at the University of South Florida and lead author of the study.
For María José Martínez Madrid — coordinator of the Chronobiology working group of the Spanish Sleep Society (SSS) — these results fully coincide with past scientific evidence, which indicates that night shifts and rotating shifts “make it difficult to fall asleep and stay asleep, while they reduce the duration and quality of sleep and cause alterations in circadian rhythms.”
In fact, the impact is such that shift work sleep disorder (SWSD) is already recognized by the medical community. The disorder is characterized by the presence of insomnia and excessive sleepiness. Its development, the coordinator adds, is due to the desynchronization that occurs between work hours and the internal circadian clock: “When work is done at times that don’t coincide with the natural phases of sleep and wakefulness, a sleep debt accumulates. Holidays and/or weekends become the opportunity to compensate for this debt, although this recovery is never complete, since lost sleep isn’t recovered proportionally.”
In this regard, Martínez recommends that employees who work shifts maintain a sleep schedule that’s as regular as possible — even during days off — and plan strategic naps before or during night shifts. She also calls on companies to facilitate access to lounges and encourage the possibility of short naps during long shifts, while providing education on sleep hygiene and circadian health to their workers. And, whenever possible, firms should establish shifts that respect biological rhythms.
Sedentary work and insomnia
On the other hand, according to the study, sedentary work is linked to a 37% increase in insomnia symptoms among employees. “Millions of years of evolution have prepared us to be physically active and eat during the day — outside, when there’s light — and to look for a safe space to sleep and recover at night, when it’s dark. Sedentary work — especially if it’s done in spaces with little natural lighting and nothing reminiscent of nature — can break this pattern for which our body is prepared. Therefore, this can have a negative impact on nighttime rest,” argues Manuel de Entrambasaguas, a neurophysiologist at the Hospital Clínico de Valencia.
María José Martínez Madrid agrees, emphasizing that physical activity contributes to regulating the circadian system and favors the accumulation of sleep pressure throughout the day. Prolonged sedentary work, on the other hand, can reduce this pressure and, therefore, make it difficult to fall asleep. “Furthermore, the lack of exposure to natural light — which is common in sedentary office jobs — can alter the secretion of melatonin and the feeling of nighttime sleepiness,” she warns.
“A sedentary lifestyle makes us sick,” adds De Entrambasaguas, who points out that, frequently, after a long day — in which we’ve spent a lot of time sitting — a feeling of tiredness is overwhelming: “We’re looking forward to getting home to lie down on the sofa. But this is a bad, sick tiredness: the result of a lack of activity. It’s a very different feeling from the good tiredness we feel after doing sports, or having been active by walking or hiking, when we also generate endorphins.”
For this reason, the expert considers it essential to maintain minimum levels of activity at work, taking advantage of any opportunity to exercise. This recommendation is seconded by Martínez Madrid, who highlights the need to increase physical activity during the day, to expose oneself to natural light (especially in the mornings), to go to and from work by bike or on foot — when possible — and to take active breaks during the workday: “Getting up and moving for at least five minutes every hour can mitigate the effects of a sedentary lifestyle.”
Stress and 24-hour jobs
Crammed schedules and sedentary lifestyles aren’t the only ways in which work can affect nighttime rest. Daniel Madero, 42, has been working in Valencia for almost 20 years in a multinational technology company. He points out that, from the start, work affected his sleep, especially because of travel. However, this impact increased as he took on more responsibilities, had more people to supervise and was responsible for managing more complex projects with bigger clients.
This, he points out, has generated three situations that have directly affected his rest: “On the one hand, there are the marathon days, during which I’ve had to stay at the office until three in the morning solving a client’s problem. Then, I have to come back at nine. On the other hand, there’s stress and tension, all those problems that you have in your head, which make you go to bed with anxiety. Because of that, it’s impossible to fall asleep. And, finally, I have very restless sleep, with nightmares related to the problems I have at work,” he sighs.
“You end up building up so much stress, so much pressure, that you end up developing such a great panic about your job that it’s difficult for you to get up in the morning to face the day,” Madero laments.
According to a study published this past January, work stress — in the medium and long-term — is related to a notable increase in sleep disorders. Another study from 2023 also associated high-tension work with professionals who have short, unsatisfactory, inefficient and irregular sleep.
“Work stress causes hyperactivation of the mind. As a result, we spend the entire workday thinking about work problems, either for specific reasons, or as a discomfort or background noise. These thoughts — plus the unpleasant emotions and physical sensations that sometimes accompany them — can persist and even amplify in the stillness of the night,” Manuel de Entrambasaguas explains.
According to the neurophysiologist, this is combined with one of the characteristics of today’s societies: hyperconnectivity. This often leads to the “abusive invasion” of personal rest time, due to instant messages or work-related emails, which can promote the “hyperactivation of the mind, which is typical of insomnia.” Meanwhile, sitting in front of the computer at night to finish pending work tasks — in front of inadequate light sources — leads to insufficient sleep.
According to De Entrambasaguas, work stress and sleep have a bidirectional relationship, which can lead employees to fall into a kind of vicious circle. Stress at work — as scientific evidence shows — can cause a deterioration in sleep. And, in turn, the lack of restful sleep negatively affects our functioning the next day and can negatively interfere with the psychological mechanisms that allow us to solve tasks or problems. This generates stress at work, and — once again — non-restorative sleep. Ultimately, according to the results of a study published in 2019, this can have harmful implications for cardiovascular health. The combination of work stress and a lack of sleep increases the risk of coronary and cardiovascular mortality in workers with hypertension.
As the neurophysiologist notes, the available scientific evidence reliably links poor or insufficient sleep with a higher risk of accidents, absenteeism and presenteeism at work, comorbidity with other physical and mental illnesses, lower productivity, less creativity and worse relationships with colleagues and clients. “Based on this evidence,” he concludes, “it seems clear that taking care of sleep benefits everyone… both employers and employees.”
Translated by Avik Jain Chatlani.
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