Journal of Occupational Health
Online ISSN : 1348-9585
Print ISSN : 1341-9145
ISSN-L : 1341-9145
Original Articles
Work e-mail after hours and off-job duration and their association with psychological detachment, actigraphic sleep, and saliva cortisol: A 1-month observational study for information technology employees
Tomohide Kubo Shuhei IzawaHiroki IkedaMasao TsuchiyaKeiichi MikiMasaya Takahashi
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2021 Volume 63 Issue 1 Article ID: e12300


Objective: A sufficient duration of time off after work is necessary to ensure workers’ health. Better quality of off-job time can also facilitate recovery from fatigue, but its quantitative influence is largely unknown. We aimed to examine how off-job time quality (as measured by the frequency of emailing after work), and off-job duration is associated with psychological detachment, actigraphic sleep, and saliva cortisol using a 1-month observational study.

Methods: The participants were 58 daytime employees working at an information technology company. Sleep actigraphy and saliva cortisol as well as self-reported outcomes were repeatedly measured for 1 month. Two-way (work e-mail frequency × off-job time) multilevel mixed-effects linear regression analyses were performed in both continuous and categorical variables.

Results: The frequency of work e-mailing after hours was significantly associated with self-reported outcomes and actigraphic sleep quality, while a significant association was not found in cortisol awakening responses and actigraphic sleep duration. A significantly larger cortisol response after awakening was found in shorter, rather than longer, durations of off-job time. Self-reported detachment, rumination and carry-over fatigue showed significant interactions between work e-mail and off-job time, suggesting that worse outcomes were found in a higher frequency of work e-mail even when employees had longer amounts of off-job time.

Conclusion: Our findings suggest that ensuring the quality and duration of off-job time is beneficial for recovery from work with sufficient sleep. Specifically, the frequency of e-mailing after work should be minimized to make recovery complete.

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© 2021 The Authors. Journal of Occupational Health published by John Wiley & Sons Australia, Ltd on behalf of The Japan Society for Occupational Health.

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