What Answering Work Messages After Hours Does to Your Sleep and Focus

This study went beyond self-report, fitting 98 information technology professionals with actigraphy devices to objectively track their sleep and giving them a standard psychomotor vigilance test, a simple, well-validated measure of reaction time and attentional lapses, each day over a nine-day period. On days with more work-related electronic communication outside normal working hours, whether emails, messages or calls, participants showed worse next-day fatigue and slower, less consistent reaction times on the vigilance test. This held true whether people were working from an office or from home, suggesting it isn't the location of work that matters but whether the working day genuinely ends.

With 98 participants from a single industry and a relatively short observation window, this is a modest-sized study, and it can't rule out that people prone to overwork also happen to sleep and perform differently for other reasons. Its strength is combining objective measures, real sleep tracking and a genuine attention test, rather than relying purely on how tired people said they felt, which gives the finding real weight for anyone whose evenings are regularly interrupted by a notification.