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The day-today variations of sleep and physical activity are associated with various health outcomes in adults, and previous studies suggested a bidirectional association between these behaviors. The daily associations between sleep and physical activity have been examined in observational or interventional contexts. The primary goal of the current systematic review and meta-analysis was to summarize existing evidence about daily associations between sleep and physical activity outcomes at inter-and intraindividual level in adults. A systematic search of records in eight databases from inception to July 2019 identified 33 peer-reviewed empirical publications that examined daily sleep-physical activity association in adults. The qualitative and quantitative analyses of included studies did not support a bidirectional daily association between sleep outcomes and physical activity. Multilevel meta-analyses showed that three sleep parameters were associated with physical activity the following day: sleep quality, sleep efficiency, and wake after sleep onset. However, the associations were small, and varied in terms of direction and level of variability (e.g. inter-or intra-individual). Daytime physical activity was associated with lower total sleep time the following night at an inter-person level with a small effect size. Future studies should examine sleep and physical activity during a longer period and perform additional sophisticated statistical analyses.

Although higher physical activity (PA) levels are associated with better mental health, previous findings about the shape of the dose–response relationship between PA and mental health are inconsistent. Furthermore, this association may differ according to sedentary levels. We investigated the cross-sectional dose-response associations between objectively measured PA and mental health in a representative national sample of adults. We also examined whether sedentary time modified the PA—mental health associations. Based on 2007–2013 Canadian Health Measures Survey data, PA and sedentary time were measured using accelerometry among 8150 participants, aged 20 to 79 years. Generalized additive models with a smooth function were fitted to examine associations between minutes per day of moderate and vigorous PA (MVPA), light PA (LPA), daily steps (combined or not with sedentary time) and self-rated mental health. A significant curvilinear relationship between average daily minutes of MVPA and mental health was observed, with increasing benefits up to 50 minutes/day. For LPA, a more complex shape (monotonic and curvilinear) was found. For daily steps, inverted U-shaped curve suggested increasing benefits until a plateau between 5 000 and 16 000 steps. The MVPA-LPA combination was significantly associated with mental health but with a complex pattern (p < 0.0005E-06). The tested PA-sedentary time combinations showed that increasing sedentary time decreased the positive PA-mental health associations. Non-linear dose-response patterns between the PA modalities and self-reported mental health were observed. Optimal doses of daily minutes of MVPA, LPA, MVPA combined with LPA and daily steps are independently associated with better mental health in adults. The results also suggest that PA-mental health associations could be hampered by daily sedentary time.

BackgroundThe climate change manifestations are associated with dramatic consequences for human health and threat physical activity behaviors.ObjectiveThe aims of this systematic review were to present the potential bidirectional associations between climate change consequences and physical activity (PA) behaviors in human and to propose the first synthesis of the literature through a conceptual model of climate change and PA. MethodsStudies published before October 2019, were identified through database searches in Pubmed, PsycArticles, CINAHL, SportDiscus, GreenFILE and GeoRef. Studies examining the associations between PA domains and climate change (e.g., natural disaster, air pollution, carbon footprint) were included.ResultsA narrative synthesis was performed and the 63 identified articles were classified into 6 topics: air pollution and PA, extreme weather conditions and PA, greenhouse gas emissions and PA, carbon footprint among sport participants, natural disasters and PA and the future of PA and sport practices in a changing world. Then, a conceptual model was proposed to identify the multidimensional associations between climate change and PA as well as sport practices. The results indicated a consistent negative effect of air pollution, extreme temperatures and natural disasters on PA levels. This PA reduction will be more severe in adults with chronic diseases, higher body mass index and elderly. The sport and PA communities can play an important mitigation role in post-natural disaster contexts. However, transport related to sport practices are also a source of greenhouse gas emissions.ConclusionThe climate change consequences increasingly and disproportionately impact PA at worldwide scale. PA has two concurrent mitigation and amplification roles towards climate changes.