Wellbeing and performance in always-on knowledge work: a multifaceted investigation using digital phenotyping

Many knowledge workers struggle with ‘always-on work’, often characterised by long working hours, reduced time for rest, shorter sleep, and difficulties in switching off from work. These factors may compromise wellbeing and performance. However, several opportunities remain to further our understanding of how always-on work factors interact and influence wellbeing and performance outcomes. This thesis sought to address this issue by applying digital phenotyping to gather concurrent data concerning always-on work factors among knowledge workers in a natural setting. Chapter Four examines the combined effects of working hours, non-work time and sleep duration and how reallocations of time are associated with state anxiety. Chapter Five explores the effects of post-work alcohol consumption and physical activity on unwinding from work in the context of physiological and psychological recovery. Chapter Six investigates whether Heart Rate Variability (HRV) may act as an index of physiological resources which indicates readiness to perform knowledge work. Chapter Seven describes an observation of the co-occurrence of positive affect and higher cognitive performance. Chapter Eight simulates redistributions of time between work, rest, and sleep to reveal which of these factors is associated with the greatest influence on cognitive performance.

This thesis’ findings indicate that a reduction in the length of the working day in favour of non-work time after work while holding sleep duration constant was associated with the greatest decrease in state anxiety. While alcohol may appear to provide temporary respite from the psychological demands of always-on work, it comes at the cost of significantly impaired physiological recovery, as measured by HRV. In contrast, physical activity was associated with greater psychological detachment with a smaller negative influence on physiological recovery. The significant association between HRV and productivity, causally mediated by motivation, indicates that HRV measurement may provide knowledge workers with insights concerning their ‘readiness’ to perform. The observation of the co-occurrence of higher positive affect and higher cognitive performance supports the notion that positive affect is a vital personal resource for performance. Finally, the greatest improvements in cognitive performance were associated with reallocating work time to sleep while holding non-work time constant. Together, the findings of this thesis highlight the challenges associated with always-on work while emphasising that wellbeing, in the form of sufficient rest, adequate sleep, healthy unwinding, and replenished physiological and psychological resources, provide the foundation for sustainable performance in knowledge work.