Shift Work

Permanent Night Shift: Is it Better than a Rotation?

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It is well known that constantly alternating between day shifts and night shifts causes stress on the body, disrupts circadian rhythms and increases the risk of poor health. Given this, and if given the opportunity, you may be tempted to choose a shift schedule consisting exclusively of night shifts.

The potential advantages of permanent night shift

Although a permanent night shift schedule forces you into opposition with the biggest external synchronizer of circadian rhythms – light exposure – it provides an opportunity for consistent sleep and wake times. A consistent sleep schedule is regularly touted as one of the most important factors for healthy sleep.

Stick to a sleep schedule. Go to bed and wake up at the same time every day, even on the weekends.

– Advice from Dr. Matthew Walker, author of Why We Sleep

This schedule also makes it easier to keep consistent meal times; another key component to maintaining healthy circadian rhythms.

But how many workers actually show full circadian adaptation to their night shift schedules? And for those that do, what sacrifices must be made to get there? This article explores these questions and more, to help you determine whether a permanent night shift schedule is likely to lead to improved health.

Circadian adaptation to night shifts

Any benefit from permanent night shifts would result from workers’ circadian systems completely entraining with the night shift hours. This expected entrainment is why many assume a rotation to be worse. However, a 2008 meta-analysis on this topic paints a different picture.

To determine if a worker’s internal clock had entrained with the night shift schedule, the researchers measured shifts in the timing of melatonin rhythms. Melatonin offers the most reliable results in regards to the circadian status of shift workers[1].

Their results indicate that only a very small minority (less than three percent) of permanent night workers show complete circadian adjustment, and less than twenty-five percent adjust to the point where any benefit is derived[2].

There are however some notable exceptions where the majority of workers do adapt. But before we get to the exceptions, let’s look at the hurdles workers must overcome in order to align their circadian rhythms with their night shift schedules.

Social impact

To experience the benefits of a permanent night shift schedule, one has to maintain the same sleeping patterns on days off – a tall order for anyone trying to maintain a social life.

Shift workers are already at a disadvantage for social interaction, as our schedules often require work during the rest of the population’s off-hours. By sleeping during a portion of the day when everyone else is awake (on both work days and off-days), you will limit opportunities for social interaction even further.

Impact on family

Continuing with a permanent night-shift schedule becomes even more problematic once you have a family. Relationships require time to build and to maintain.

Even given the slim possibility your significant other happens to have the same shift schedule as you, adding children to the mix will necessitate at least one of you sacrifice your sleep routine – I’m not aware of any night classes for school-age children. Your child’s social life and extracurricular activities must be considered as well if you wish to give them the best chance at succeeding in life.

The effect your schedule could have on your family’s health is another important point to consider. Your loved ones will no doubt alter their sleep and social schedules in order to spend more time with you. Altering sleep and eating patterns in this way creates what Satchin Panda, researcher at the SALK institute for biological studies, refers to as “secondhand shift workers”, and predisposes them to the same chronic diseases as shift workers[3].

In regards to children specifically, a review of published papers on this topic revealed that children of shift workers had more cognitive and behavioural problems, as well as higher rates of obesity compared to children raised by non-shift workers[4].

Depression

Eschewing personal relationships and social interaction in favor of your work and sleep schedule comes with another potential problem: depression. A ten year study following 4,642 adults found that risk of depression was significantly greater among those with social strain, lack of social support, and poor overall relationship quality[5].

There is also evidence that people who are disconnected from others are more likely to die early[6]. In fact, social isolation has been shown to increase risk of illness and early death as much as other known risk factors such as high blood pressure, obesity, lack of exercise and smoking[7].

Exceptions to the rule

I mentioned exceptions earlier. Now that we’ve covered the challenges faced by permanent night shift workers, we can begin to understand what type of environment might be necessary to see any advantages from the schedule.

Rates of circadian adaptation are much higher for isolated work environments, such as Antarctica[8, 9] and North Sea oil rigs[10, 11]. Most workers in these environments shift their circadian system to align with the new night-shift schedule within a week.

In these unusual situations, adaptation is facilitated by many factors. Most notably, the isolated environment leads to a lack of social and family obligations. Also, as work and sleep take place in the same location, there is no requirement to travel home in sunlight.

Seasonal changes may play a role as well. Winter in these extreme latitudes consists of twenty-four hour darkness for three months, making conflicting light exposure a nonissue.

Genetic predisposition and conclusion

There is some evidence that a a small subset of the population can adapt more readily to night shifts[11, 12]. Your chrontype and genotype may even lead you to prefer the evening or night shift.

But before signing on for such a schedule, you should consider the many factors that will impact, both negatively and positively, your quality of life.

Photo by Florian Pérennès on Unsplash

References:

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