The effects of circadian misalignment and work shift on oxidative stress profile of shift workers have not been explored in the literature. The present study aimed to evaluate the role of shift work (day and night) and social jetlag – a measure of circadian misalignment – with oxidative stress markers.

A cross-sectional study was performed with 79 men (21-65 years old, 27.56 ± 4.0 kg/m2) who worked the night shift (n = 37) or daytime (n = 42). The analyzed variables included anthropometric measures and determination of systemic levels of markers of oxidative damage and antioxidant defense. Social jetlag was calculated by the absolute difference between the mean sleep point on working and rest days. The night group presented higher systemic values of thiobarbituric acid reactive substances and hydrogen peroxide, and lower levels of nitrite, total antioxidant capacity, and catalase and superoxide dismutase activities in relation to the day group. However, social jetlag was not associated with oxidative stress-related biomarkers analyzed in the night group. These results suggest that the night worker has higher levels of oxidative stress damage and lower levels of antioxidant defenses, while social jetlag was not a possible responsible factor for this condition.