STRESS AND AROUSAL CIRCADIAN RHYTHMS IN SMOKERS AND NON-SMOKERS WORKING DAY AND NIGHT SHIFTS

Abstract

Twenty smokers and twenty non-smokers completed a brief Mood State Questionnaire every 2 hours, over one day shift and one night shift. The subjects comprised male police oAcers and factory workers, aged 23‐57 years. Cigarette smokers reported significantly higher stress levels than non-smokers on both day and night shiftsOp< 0:05U. This confirms previous findings that smokers are often more stressed than non-smokers. Stress levels varied over time within each shiftOp< 0:001U, but the circadian patterns did not diAer between smokers and non-smokers. Thus smoking did not alter circadian mood rhythms, nor did it facilitate stress control. Self-rated levels of arousal showed the archetypal inverted-U pattern over time in both smokers and non-smokers. There was no diAerence in mean arousal levels between subgroups, indicating that cigarettes did not lead to greater alertness. The shift time interaction was significant for both stressOp< 0:001U and arousalOp< 0:003U, indicating diAerent circadian rhythms during the day shift and the night shift. Finally, while smokers consumed slightly more cigarettes during the night shift than day shift (22.3, 19.4 respectively, p< 0:05), mean stress and arousal levels did not diAer between shifts. The implications of these findings for smoking behaviour are discussed. #1997 by John Wiley & Sons, Ltd.