“The Effects of Cigarette Smoking on Overnight Performance”, 1998-03-01 (; backlinks; similar):
15 healthy smokers and 15 non-smokers were enrolled into this study investigating the effects of smoking on overnight performance. Subjects arrived at the test center at 7:30PM and were assessed at baseline (8PM) and at 10PM, midnight, 2AM, 4AM, 6AM, and 8AM hours on a battery of tests (including Critical Flicker Fusion, CFF; Choice Reaction Time, CRT; Compensatory Tracking Task, CTT; Short Term Memory Task, STM; and the Line Analogue Rating Scale, LARS).
Results showed that the performance of the smokers was more consistent with baseline measures than that of the non-smokers, which became more impaired throughout the night on a number of tasks [CFF (p < 0.005), Total Reaction Time (TRT, p < 0.05), CTT (p < 0.05) and the Reaction Time (RT) aspect of the CTT task (p < 0.0005)]. The Recognition Reaction Time (RRT) aspect of the CRT task showed that the performance of the non-smokers became more impaired from baseline (p < 0.005), while that of the smokers remained at baseline levels until 0400 hours, when it deteriorated to become comparable to that of the non-smoking controls. Subjective sedation ratings (LARS) resulted in comparable levels of impairment for both study groups (p < 0.00005).
Findings from the STM task failed to reach statistical-significance.
These data suggest that when performance is being measured overnight, smokers show little or no impairment, whilst the performance of non-smokers showed performance decrements.