Naps and Caffeine as Countermeasures to Sleep Problems of Night-Shift Work

               As a person who has worked the night shift before, I can attest to how difficult it is to stay awake and perform duties on the same efficacy of day time work. Performance in regards to skills, reaction time, logical reasoning, and spatial orientation are heavily reduced, to approximately 10-35% of the mean level of performance in the daytime. Therefore, research into potential countermeasures for sleep problems associated with the night-shift is increasingly popular to those who suffer from reduced mean performance. In this examined study, napping and caffeine as a combined treatment was observed, with the goal of increasing work performance.

               Most of the causes for reduced work performance originate from the circadian rhythm and homeostatic sleep pressure preceding work time.  Night work inherently disrupts the critical temporal relationship of the circadian and homeostatic factors that mediate sleep and alertness; it does not allow for the circadian rhythm to counteract increasing homeostatic drive for sleep during work hours, while also interfering with attempted sleep during daytime. Furthermore, the ability of the body to adapt to such patterns of sleep does not occur even after two or three weeks of night time working. While napping and caffeine usage were previously studied before, no previous studies had combined the two measures and observed their effects before.

               The procedure involved 4 experimental groups: 1) A 2.5 hour nap prior to two of the four consecutive night shifts plus a caffeine placebo taken prior to all four nights (NAP); 2) Ingestion of 4 mg/kg of caffeine prior to all 4 night shifts (CAF); 3) A combination of the two prior groups (NAP+CAF); 4) A caffeine placebo prior to all 4 night shifts with no naps (PBO). Statistical analysis of the tests of executive functioning showed that caffeine, napping, and a combination of caffeine and napping improved both alertness and performance during all four night shifts, with the combination treatment being the most effective. Furthermore, the countermeasures were able to reduce sleep pressure during the sleep time after the night work, thus decreasing sleep deprivation by preventing disruptions to sleep during the daytime. Much of the study, however, contains methodological discrepancies, such as the varying ages of the participants. It does serve to show that combining naps and caffeine may be the optimal way to improve performance during night work. 

Schweitzer, P., Randazzo, A., Stone, K., Erman, M., Walsh, J. (2006). Laboratory and Field Studies of Naps and Caffeine as Practical Countermeasures For Sleep-Wake Problems Associated With Night Work. SLEEP. 29(1): 39-50.