A few years ago the Trade Union Congress revealed that the number of workers doing night shifts had risen by 5% in recent years, with women contributing around two-thirds of this increase.

“Tonight, most of us can look forward to an extra hour in bed. But as we sleep, millions of workers will be busy keeping the UK ticking over,” the researchers explain. “Whether its nurses looking after patients or taxi drivers getting people home safely, we all depend on Britain’s army of night workers.”

Night shift work can be harmful to health in several ways:

• Disrupting circadian rhythms: The body’s internal clock is set to sleep at night and be awake during the day. Night shift work disrupts this natural pattern, leading to a misalignment of the body’s circadian rhythms. This can cause problems with sleep, digestion, and other bodily functions.
• Sleep disturbances: Night shift workers often have trouble getting enough quality sleep during the day. This can lead to sleep deprivation and fatigue, which can increase the risk of accidents and mistakes on the job.
• Increased risk of chronic diseases: Studies have shown that night shift workers are at an increased risk of developing chronic diseases such as heart disease, diabetes, and certain types of cancer. This may be due to the disruption of the body’s natural rhythms and increased exposure to artificial light at night.
• Mental health issues: Night shift workers may be more prone to anxiety, depression, and other mental health problems due to the disruption of their sleep and social rhythms.
• Social isolation: Night shift workers may have difficulty maintaining social relationships and participating in regular activities with friends and family due to their work schedule.

Overall, while working the night shift may be necessary for some professions, it can have negative effects on both physical and mental health in the long run.

Genetic protection

The researchers utilized the UK Biobank, a cohort of 53,211 workers spanning from 2006 to 2018 were examined for their genetic inclination towards “eveningness” to determine the effects of night work on sleep.

The study revealed a significant reduction in sleep for night workers, with the greatest impact observed among those who consistently worked nights. Given the essential role of sleep in maintaining physical and mental well-being, this finding is of considerable concern.

The CHRONO research team also discovered that individuals who frequently worked night shifts slept less overall, with regular night shift workers reporting 13 minutes less sleep per night compared to those who never worked such hours. However, the study also found that those with a higher genetic predisposition to “eveningness” experienced a protective effect, resulting in a reduction of the sleep penalty by up to 28%.

“In this study, we conducted a Genome-Wide Association Study (GWAS) of eveningness, which allowed us to measure the genetic propensity of being an evening person,” the researchers explain. “What we found particularly exciting is that we were able to use multiple measures of eveningness including genetic, self-reported, and accelerometer measures to advance our knowledge of sleep penalties among night shift workers.”

Protecting against harm

Suffice it to say, it’s perhaps unlikely that managers will be genetically testing employees before determining whether to assign them to night shifts or not, so the best approach is to try and limit the harm for all workers instead. There are a number of ways that managers can do this.

• Limiting the number of consecutive night shifts: Studies have shown that working consecutive night shifts can lead to sleep deprivation and other health problems. Therefore, limiting the number of consecutive night shifts and providing enough time for workers to rest between shifts can help prevent the negative effects of night work.
• Providing adequate break time: Employers can also ensure that workers are provided with adequate break time during night shifts. Short, frequent breaks can help workers stay alert and reduce fatigue.
• Adjusting work schedules: Employers can adjust work schedules to accommodate workers’ individual needs and preferences. For example, workers with a genetic predisposition to eveningness could be scheduled for later shifts to help reduce the impact of night work on their sleep.
• Educating workers: Educating workers on the importance of sleep and how to maintain healthy sleep habits can help them cope with the challenges of night work. This could include providing information on how to create a conducive sleep environment, how to wind down after work, and the importance of good nutrition and exercise.

Overall, protecting workers against the harm of night shifts requires a multi-faceted approach that considers the individual needs of workers, their working conditions, and the broader organizational and societal factors that contribute to night work.