Oxidative stress increased in healthcare workers working 24-hour on-call shifts

Long work hours, night shifts, stressful situations and insufficient social support increase levels of anxiety and depression and decrease motivation to perform among healthcare professionals. In this study, we evaluated oxidative stress levels in medical residents working 24-hour on-call shifts, and in nurses, relative to non-healthcare hospital staff in sedentary positions. We also measured serum prolidase activity, a measure of collagen turnover, as an objective proxy for level of physical activity.

Fifty-five male and 15 female medical residents on 24-hour, in-house, on-call duty, and 45 nurses and 30 (15 male/15 female) non-healthcare staff working 8-hour shifts were recruited. All were healthy nonsmokers. Parameters of oxidative stress and serum prolidase activity were measured twice for each subject, upon arising at 8 am after an overnight fast; and then again near the end of the work shift, or after 16 hours of consecutive work (at 12 pm) for residents.

After hours of continuous work, serum total oxidative status and the oxidative stress index increased significantly, whereas total antioxidant status decreased (all P < 0.0001) in healthcare staff (nurses, male and female residents). All these variables remained virtually unchanged in non-healthcare staff. Similarly, serum prolidase activity increased in healthcare staff (P < 0.0001), but failed to increase statistically in non-healthcare staff.

Healthcare workers suffer increased oxidative stress after prolonged work hours, especially while still on duty. Possible mechanisms for this include increased workload and, perhaps, psychological stress as well. However, long-term studies are needed to clarify the effects of sustained exposure to oxidative stress.