Can Working on Night Shifts Have Effects on Your Health?

In countries like Mexico, almost one million people will work night shifts in 2023, but 3.5 million workers will rotate shifts.
a woman works at night in her computer
Working at night negatively impacts alertness, performance and cognitive abilities (Photo: Getty Images).

Sleeping more hours before starting a shift, achieving eight hours of sleep on workdays, and taking a nap of more than one hour are some scientific recommendations for individuals employed at night shifts, without these being detrimental to their health.

In Mexico, it was recorded that more than 931,000 people work night shifts, while 3,523,000 have mixed schedules, according to information from the National Survey of Occupation and Employment by the National Institute of Statistics and Geography (INEGI). It is estimated that 1 out of 5 workers worldwide are engaged in night shift jobs, according to the World Health Organization in 2019.

Working at night in certain sectors such as public health services, transportation, communication, commerce, and leisure may be unavoidable, but according to several studies, taking these shifts is associated with various health issues.

What Are The Consequences Of Working At Night?

Working during the biological night is associated with many negative repercussions for health, sleep and cognitive functioning, according to the study Move the night way: how can physical activity facilitate adaptation to shift work? published in March 2024 by researchers from the School of Health, Medical and Applied Sciences, Central Queensland University.

Other health problems such as accidents, type 2 diabetes, some types of cancer (breast, prostate, colon and rectum), coronary heart disease and stroke are reported in the 2023 study, Improving performance on night shift: a study of resident sleep strategies, published in the Journal of Clinical Sleep Medicine.

The negative consequences of night work “result from circadian misalignment, which broadly is a term that refers to the mismatch between the timing of sleep and wake, the light dark cycle, and other circadian rhythms”, such as behavioral, physiological, hormonal and cellular as defined by the the Queensland researchers.

According to the investigation, misalignment can be internal (for example, rhythms not aligned with each other) or external ( such as rhythms not aligned with environment) which has implications for health and wellbeing.

Other consequences associated with circadian rhythm disruption include increased blood pressure and inflammatory markers, reversed cortisol rhythms, reduced heart rate variability, and decreased insulin sensitivity.

In the Journal of Clinical Sleep Medicine the 2023 study also reports negative impact on alertness, performance, and cognitive abilities.

For instance, while analyzing the cognitive performance of Intensive Care Units physicians in a 2016 investigation that’s quoted on the Journal’s study, 51 intensivists were evaluated in these areas and found that the cognitive abilities of the intensivists were significantly altered following a night shift in the ICU.

Other researchers such as Ann Dyreborg Larsen, found in her study Night shift work and sickness absence – many for the few or few for the many?, that night shift workers with more than 150 night shifts per year had 5 more sick days than employees with no night shifts.

What Can Be Done To Mitigate Health Risks?

Although the first solution could be the intake of natural stimulants such as caffeine, in reality it has been found in the Journal of Clinical Sleep Medicine that the consumption of this beverage had no significant effects on Performance Effectiveness.

Over half of residents consumed caffeine during their night shifts and there was no difference in Performance Effectiveness between residents who used caffeine and those who did not.

On the other hand the recommendations that have been made for those people who have night jobs or mixed shifts are as follows:

Sleeping for one or more horse during a nocturne shift boosts performance. “Residents who were able to sleep 1 or more hours during night shifts had a nearly significantly higher mean Performance Effectiveness than residents who slept less than an hour”, says the Journal of Clinical Sleep Medicine research.

By increasing the hours of sleep before starting duty and getting more than 8 hours of sleep per day during the work week, it leads to better performance.

When adapting to a new night shift, it is recommended to rest for 9 hours a day continuously, prior to going on duty.

Reducing to at least three consecutive night work, having an interval of more than 11 hours between shifts and a shorter shift length per day can help diminish circadian disruption of employees, according to the study How to schedule night shift work in order to reduce health and safety risks authored by Scandinavian Journal of Work, Environment & Health researchers.

When exposed to sunlight in the event of a shift change, light-blocking glasses are recommended. “Logistically, it may not be possible to avoid light during the shift or the drive home and therefore optimising light exposure is challenging”, the Queensland investigation notes.

Physical activity during and after the working hours in the night can help to better adapt to the schedule and mitigate the long-term consequences..

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Estefania Camacho