The effect of total sleep deprivation on cognitive performance during night-shift for early and late chronotypes

A single night of total sleep deprivation (TSD) impairs cognitive performance. Many shift workers struggle to transition to nightshift and have been awake for at least 24 hours by the end of their first night-shift. Evidence suggests chronotype, an individual difference which reflects circadian phase, also affects cognitive performance during nightshift. The aim of this study was to examine the impact of chronotype on the effect of TSD on cognitive performance during night-shift. As early types are suggested to experience greater circadian misalignment during nightshift than late types, early types were predicted to perform worse than late types over the night-shift. However early types were predicted to outperform late types towards the end of the night-shift, due to increased alertness associated with their advanced circadian phase.