The Impact of Sleep, Physical Activity and Sedentary Behaviour on Symptoms of Depression and Anxiety Before and During the COVID-19 Pandemic in a Sample of South African Participants

Raphaella Lewis, Laura Roden, Karine Scheuermaier, F.X. Gómez-Olivé, Dale E Rae, Stella Iacovides, Alison Bentley, Jonathan Davy, Candice Christie, Swantje Zschernack, Johanna Roche, Gosia Lipinska

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    During lockdowns associated with the COVID-19 pandemic, individuals have experienced poor sleep quality and sleep regularity, changes in lifestyle behaviours, and heightened depression and anxiety. However, the inter-relationship and relative strength of those behaviours on mental health outcomes is still unknown. We collected data between 12 May and 15 June 2020 from 1048 South African adults (age: 32.76 ± 14.43 years; n = 767 female; n = 473 students) using an online questionnaire. Using structural equation modelling, we investigated how insomnia symptoms, sleep regularity, exercise intensity/frequency and sitting/screen-use (sedentary screen-use) interacted to predict depressive and anxiety-related symptoms before and during lockdown. We also controlled for the effects of sex and student status. Irrespective of lockdown, (a) more severe symptoms of insomnia and greater sedentary screen-use predicted greater symptoms of depression and anxiety and (b) the effects of sedentary screen-use on mental health outcomes were mediated by insomnia. The effects of physical activity on mental health outcomes, however, were only significant during lockdown. Low physical activity predicted greater insomnia symptom severity, which in turn predicted increased depressive and anxiety-related symptoms. Overall, relationships between the study variables and mental health outcomes were amplified during lockdown. The findings highlight the importance of maintaining physical activity and reducing sedentary screen-use to promote better sleep and mental health.

    Original languageEnglish
    Article number24059
    JournalScientific Reports
    Publication statusPublished - 15 Dec 2021

    Bibliographical note

    Open Access This article is licensed under a Creative Commons Attribution 4.0 International License, which permits use, sharing, adaptation, distribution and reproduction in any medium or format, as long as you give appropriate credit to the original author(s) and the source, provide a link to the Creative Commons licence, and indicate if changes were made. The images or other third party material in this article are included in the article's Creative Commons licence, unless indicated otherwise in a credit line to the material. If material is not included in the article's Creative Commons licence and your intended use is not permitted by statutory regulation or exceeds the permitted use, you will need to obtain permission directly from the copyright holder.


    G.L. is supported by the National Research Foundation (NRF; South Africa), Competitive Support for Unrated Research (CSUR) grant number 116229.


    • COVID-19 pandemic
    • sleep health
    • exercise
    • physical activity
    • screen-use
    • sedentary behaviour
    • depressive symptoms
    • anxiety symptoms
    • lifestyle factors
    • structural equation modelling


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