摘要：Objectives. We analyzed the individual-level associations between participation in moderate to vigorous physical activity (MVPA) and psychological distress levels using a large, nationally representative, longitudinal sample and multivariable panel regression models. Methods. We used 3 waves of panel data from the Household, Income and Labour Dynamics in Australia Survey, consisting of 34 000 observations from 17 000 individuals and covering 2007, 2009, and 2011. We used fixed-effects panel regression models accounting for observable and unobservable confounders to examine the relationships between the weekly frequency of MVPA and summary measures of psychological distress based on the Kessler Psychological Distress Scale. Results. We found substantial and highly statistically significant associations between the frequency of MVPA and different indicators of psychological distress. Frequent participation in MVPA reduces psychological distress and decreases the likelihood of falling into a high-risk category. Conclusions. Our findings underscore the importance of placing physical activity at the core of health promotion initiatives aimed at preventing and remedying psychological discomfort. Moderate to vigorous physical activity (MVPA) is important to people’s lives, with the World Health Organization as well as national and international bodies recommending frequent participation in it. 1,2 Recent analyses of Australian population-level data have endorsed this by showing that MVPA is independently associated not only with general and physical health but also with overall levels of mental health and self-reported life satisfaction. 3 However, the relationships between MVPA and other facets of mental health, including levels of psychological distress, have not yet been well established. Psychological distress, understood as the experience of unpleasant feelings or emotions that affect day-to-day functioning, affects a sizable share of the population in developed countries such the United States, the United Kingdom, and Australia 4–7 and is known to lead to more severe mental disorders and physical health issues. 8,9 Consequently, the financial and human costs of psychological distress are non-negligible, and gaining a deeper understanding of the factors that influence individuals’ distress levels is important for the development of efficient public health policies and the devising of effective palliative interventions. Emerging evidence of an association between MVPA and overall levels of mental health has suggested that associations between MVPA and psychological distress are also likely. Potential effects may run through known physiological, psychological, and social processes. From a physiological point of view, we know that MVPA enhances fitness levels, which in turn regulate physiological stress responses, such as reduced secretion of hormones and lowered blood pressure. 10 From a psychological perspective, MVPA has been linked to reduced arousal and mood enhancement through cognitive distraction and biochemical changes, and to positive health behaviors during periods of high stress (e.g., a lower likelihood to smoke and eat unhealthily). 11 Additionally, participation in MVPA tends to increase time spent outdoors, as well as the frequency and quality of social interactions and interpersonal relationships. 12–14 As a result, we would expect MVPA to have the potential to enhance well-being by reducing psychological distress. Consistent with these theories, results from the limited body of existing empirical research have suggested that there are indeed negative associations between the frequency of MVPA and psychological distress levels. However, these findings have emerged almost exclusively from analyses of small nonprobability samples, 15–21 and the few available studies based on nationally representative samples are cross-sectional (e.g., Scotland 22 and Singapore 23 ). The small, nonprobability nature of the samples used in these studies means that findings are tentative and cannot be generalized to the population as a whole. Their cross-sectional nature means that longitudinal regression techniques that enable more precise estimation of the associations of interest by examining within-individual change over time and minimizing omitted variable bias attributable to unobservable factors cannot be implemented. In fact, undertaking large-scale prospective analyses is often regarded as a necessary step forward in enhancing current knowledge of the associations between MVPA and psychological distress. 6,23 In this article, we fill this gap and add to the literature by establishing the population-level associations between the weekly frequency of MVPA and self-reported levels of psychological distress with a nationally representative Australian panel data set and fixed-effect (FE) panel regression models.
