Nurses who work particularly long shifts at the hospital may face a greater risk of feeling horrible about their job, according to a recent study published in BMJ Open.

The authors analyzed data taken from the RN4CAST study, a cross-sectional survey taken of registered nurses in 12 countries across Europe, focusing on the relationship between the amount of hours worked during the nurses’ last shift and their reported job satisfaction, intention to leave their current job, and their risk of burnout. Burnout risk was measured by the three separate dimensions of emotional exhaustion, depersonalization, and personal accomplishment.

Ultimately studying 31,627 nurses working in 488 hospitals, the authors found that 25 percent of nurses felt some degree of job dissatisfaction; 33 percent expressed a desire to leave their current job; and 27 percent felt emotionally exhausted. More interestingly, the authors saw a distinctive pattern for nurses who worked the longest shifts.

“We found that shifts of 12 hours or more for hospital nurses are associated with more reports of burnout, job dissatisfaction, dissatisfaction with work schedule flexibility and intention to leave,” they concluded. “Additionally, all shifts longer than 8 hours appeared to be detrimental to nurses’ job satisfaction.”

In particular, the odds of wanting to leave their current job increased by 31 percent for nurses who worked 12 hours or more compared to those who only worked 8 or fewer.

Though only about 15 percent of the nurses surveyed worked over 12 hours, the authors note that the practice has become increasingly popular in hospitals, due to the belief that longer shifts can provide nurses more flexibility and days off, as well as promote efficiency, and in countries such as Poland and Ireland, it’s commonplace.

As the authors point out though, “These scheduling practices have not been systematically evaluated and the movement to longer shifts for nurses has not been based on research evidence of improved outcomes for nurses and an absence of harm to patients.”

Coupled with other studies, including those performed in the US, the researchers believe that employers and nurses alike should be made more aware of the potential consequences that can come with long work shifts.

“Nurses may prefer working only three shifts of 12 hours per week, however it appears to be at the expense of their psychological well-being,” they wrote. ”Employers should be aware of the multiple consequences of burnout, including higher risks of medical error, decreased quality of care, reduced well-being, and economic loss through increased absenteeism and higher turnover rates.”

Source: Dall-Ora C, Griffiths P, Ball J, et al. Association of 12 h shifts and nurses’ job satisfaction, burnout and intention to leave: findings from a cross-sectional study of 12 European countries. BMJ Open. 2015.