Help Me Make it Through the Night (Shift)

Laura A. Stokowski, RN, MS


January 24, 2012

In This Article

Adaption to the Night Shift

Recently, a research team at Vanderbilt University examined how chronotype, along with an individual's sleep strategies, might influence how well a nurse adapts to the night shift.[40] Gamble and colleagues hypothesized further that genetics, and in particular the body's "clock" genes, might play a role in how well a nurse adapts to working nights.

They recruited a convenience sample of 388 nurses who worked 12-hour shifts (days or nights) at a university hospital. Most (331) were women, and their average age was 36.5 years (range, 22-76 years). Participants completed self-reported surveys on sleep-wake patterns and had blood drawn for genetic analyses. "Adaptation" was a composite of variables, such as how the nurses felt, fatigue levels, regularity of sleep patterns, how long it took them to get out of bed, how much caffeine they ingested, and how likely they were to fall asleep during the day.

The researchers found that night-shift nurses reported significantly poorer adaptation to their work schedules than day-shift nurses. The former group had significantly later chronotypes than the latter. Examining the relationship between chronotype and adaptation to shift work, they found that earlier chronotypes had higher adaptation scores for the day shift and lower scores for the night shift. Later chronotypes had intermediate adaptation scores for both day and night shifts.

Although previous research has found that night-shift nurses get fewer hours of sleep than day-shift nurses,[27] sleep duration in this study did not differ between day- and night-shift nurses. However, that night shift nurses had poorer adaption to their work schedules suggests that adaption is affected not only by how much sleep a nurse gets but when he or she sleeps relative to working. This, in turn, is influenced by an individual's sleeping patterns -- the strategies an individual uses for switching back to a normal sleep schedule on days off from work and for reverting back to nights.

In the genetic analyses of the nurses, some changes in the "clock" genes were associated with alcohol and caffeine consumption and sleepiness, as well as sleep characteristics. Many of these results were specific to the type of shift, suggesting an interaction between the genes and the environment (in this case, the "environment" was shift work).

This study was unique in identifying and describing both the working and off-working sleep strategies of night shift nurses. A few nurses remain on "nights" even on their nights off -- staying up all night and sleeping during the day, a strategy favored by older and more experienced nurses. Far more common, however, was trying to switch to a "normal" sleeping schedule (eg, sleeping at night) on one's off days, a strategy followed by half of the study participants. These nurses generally tried to sleep in as late as possible on the day of their first night shift to ease the transition to nights. In contrast, a quarter of nurses deprived themselves of sleep by rising at an early hour on the day of their first night shift and forcing themselves to stay awake for 24 hours. It is perhaps no surprise that these nurses were the most poorly adapted to working nights and were more likely to report dozing off at work during sedentary activities.


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