1,721,059 research outputs found
Effects of exercise intensities on cortisol release following the induction of a psychological stressor
No full textLong-term physical activity and exercise have been shown to mitigate neurobiological responses to acute psychosocial stressors. There is also evidence that engaging in a single bout of exercise has immediate effects on reducing neurobiological reactivity to acute psychosocial stressors. However, much of this previous work applied definitions of intensity zones on American College of Sports Medicine’s global prescription recommendations, not based on individualized, physiologically meaningful cut-off points for demarcating the intensities at which participants exercised.
This project expands on prior evidence by investigating the extent to which a single bout of exercise, performed at light, moderate, or vigorous intensities – established with meaningful indicators of changes in metabolic needs – alters the neurobiological response to a subsequently induced psychosocial stressor. It is hypothesized that vigorous intensity, defined as the midway point between the first and second ventilatory thresholds, will dampen cortisol output following a subsequently induced psychological stressor, compared to moderate (defined as being 10% below the VT1) and light (set at 1.7km/hour) intensities. Moderate intensity is expected to dampen the cortisol trajectory as compared to the light intensity, but to a lesser extent than vigorous.
To achieve this, participants complete a modified maximal cardiopulmonary exercise test (CPET) to determine their individual ventilatory thresholds. Participants then return to the lab a second time to complete the experiment, whereby they are randomized to complete a 30-minute exercise at their randomized intensity zone, followed by the Trier Social Stress Test 45 minutes later.
Multilevel Growth Curve Analysis determined that participants in the vigorous group had significantly slower rates of increased cortisol compared to both the light and moderate groups. Results also indicated no significant differences in cortisol trajectories between the light and moderate groups, apart from the fact that those in the moderate group had lower estimated starting points prior to starting the TSST. Results suggest that the current findings may be a result of the negative feedback loop, if they hold when the complete sample is analyzed. Examination of other psychological and physiological responses to psychosocial stressors will help elucidate the extent to which exercise mitigates stress reactivity in its more comprehensive conceptualization.Education, Faculty ofKinesiology, School ofGraduat
Self-reported and accelerometer-recorded physical activity and cross-sectional associations with the gut microbiome : a coronary artery risk development in young adults study
No full textThe role of the gut microbiome in host physiology and its association with various diseases is a developing field of research and information on the impact of physical activity on the gut microbiome is limited, particularly in diverse population-based cohorts. This study examines the associations between physical activity with gut microbial diversity, composition, and function. Utilizing data from the Coronary Artery Risk Development in Young Adults (CARDIA) study, we evaluated the relationship between physical activity and the gut microbiome in participants aged 47-61. Physical activity was assessed through self-reported measures (n = 581) and accelerometer data (n= 364), while gut microbiome measures were analyzed using whole genome shotgun (WGS) sequencing. We employed regression models for cross-sectional analyses, adjusting for sociodemographic and behavioural covariates, such as diet, as well as body mass index (BMI). Self-reported physical activity showed significant positive associations with beta diversity and negative associations with species richness, a measure of alpha diversity, after adjusting for all factors, but no change in Shannon Diversity Index. Identification of associations with specific bacterial species, metabolic pathways and enzyme families revealed both positive and negative associations with self-reported physical activity levels, highlighting complex associations between physical activity and gut microbiota. Accelerometer data revealed significant positive associations between beta diversity and moderate-to-vigorous intensity physical activity (MVPA), with no associations with alpha diversity or specific species, metabolic pathways, and enzyme families. The study underscores the intricate association between physical activity and the gut microbiome in a middle-aged, racially diverse cohort. Our findings support the notion that regular physical activity is associated with changes in the gut microbiome, which promote improved host health, and negatively associated with metabolic functions that have been implicated in pathological states. The study's diverse demographic and robust methodology strengthen its external validity and contribute to a growing body of evidence on lifestyle factors that are associated with the gut microbiome. While these insights enhance our understanding of the multifactorial nature of gut microbiome dynamics, future studies should employ longitudinal and interventional designs with integrated methodologies for physical activity assessment, using the most up-to-date methods of DNA analysis.Education, Faculty ofKinesiology, School ofGraduat
Covid-19 pandemic and exercise for healthcare workers (COPE HCW) trial : secondary analyses examining the effects of at-home exercise on healthcare workers' multidimensional well-being
No full textBackground. Current research on employee well-being largely entails focus on physical and
mental health and illness, as well as functioning specific to the workplace. Yet, more recent conceptualizations of well-being extend beyond the presence or absence of health or illness to concepts of thriving or languishing, measured using an outcome-wide measurement approach. Accordingly, healthcare worker (HCW) multidimensional well-being as an overarching concept should be inclusive of a broad range of ill-being and well-being indictors that span multiple dimensions, including physical, psychological, and psychosocial realms of life. A recent 12- week mHealth exercise intervention for HCWs in Vancouver, BC demonstrated significant treatment effects for depressive symptoms, burnout symptoms, and absenteeism among those randomized to an exercise versus waitlist control condition. Secondary analyses were conducted to examine whether positive treatment effects could extend to a broader range of multidimensional ill-being and well-being outcomes.
Methods. Data was from the COVID-19 Pandemic and Exercise for Healthcare Workers (COPE HCW) trial, a two-arm parallel randomized controlled trial for low-active HCWs working at Providence Health Care centers across Vancouver, BC. The effects of engagement with a suite of exercise applications for 80 minutes per week for 12 weeks (vs. waitlist control) on indicators of multidimensional ill-being and well-being were examined. Treatment effects for physical health symptoms, recent global stress, work-to-personal life interference, overall physical health, overall mental/emotional health, life satisfaction, psychological flourishing, resilience, and work- to-personal life enhancement were analyzed using intent-to-treat analyses with a structural equation modelling (SEM) growth model approach.
Results. By the end of the trial, significant treatment effects were observed for all outcomes, such that those in the exercise condition (vs. waitlist control) reported significant reductions in ill-being and improvements in well-being measures. Adherence to the intervention decreased over time, and treatment effects were most apparent for those who engaged with the exercise apps the most.
Conclusions. mHealth exercise is one individual-level behavioral intervention which was successful in improving multidimensional ill-being and well-being among HCWs. Findings will help inform future employee wellness programming by providing evidence that mHealth exercise can be used as a modality to support well-being across different life domains.Education, Faculty ofKinesiology, School ofGraduat
Predicting ten-year trajectories of depressive symptoms from demographic, health, social, psychological, behavioural, and genetic factors : an analysis of the Health and Retirement Study
No full textDepressive symptoms in midlife and older adulthood are common, persistent, and associated
with cardiovascular diseases, cognitive impairment, and earlier mortality. Previous research has
identified risk factors for depressive symptoms in middle and older adulthood, such as increasing
age, female sex, race and ethnicity, major life stressors, lack of social connectedness,
neuroticism, lower life satisfaction, physical inactivity, alcohol use, and polygenic risk scores, to
name a few. However, these multi-factorial predictors have not been included in the same study
to determine their relative contribution to depressive symptoms in middle and older adulthood.
Furthermore, previous research has only assessed depressive symptoms and their predictors
cross-sectionally or prospectively (i.e., 2 time points), which misconstrues the dynamic temporal
nature of depressive symptoms. Therefore, using data from the Health and Retirement Study (N
= 13,994), the aims of this study were threefold: 1) estimate trajectories of depressive symptoms
in middle-aged and older adults using growth mixture modelling (GMM), 2) identify predictors
of trajectory groups in order of importance using random forest (RF) analysis, and 3) compare
how trajectory groups differ in relation to the most important predictors using multinomial
logistic regression (MLR). GMM indicated that there were five latent classes following distinct
trajectories of depressive symptoms over 10 years: “consistently low”, “increasing”,
“consistently moderate”, “decreasing”, and “consistently high”. Out of a total of 72 predictors
ranging from demographic to genetic factors, the top five predictors of depressive symptoms
trajectories were trait anxiety, lower life satisfaction, neuroticism, perceived constraints, and
hopelessness. MLR demonstrated that trajectory groups differed significantly in relation to
psychological, health, and social factors, which highlights potential avenues for intervention.Education, Faculty ofKinesiology, School ofGraduat
Going Beyond Counting First Authors in Author Co-citation Analysis
Full text linkThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Variations on the Author
Full text link“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
Appropriate Similarity Measures for Author Cocitation Analysis
Full text linkWe provide a number of new insights into the methodological discussion about author cocitation analysis. We first argue that the use of the Pearson correlation for measuring the similarity between authors’ cocitation profiles is not very satisfactory. We then discuss what kind of similarity measures may be used as an alternative to the Pearson correlation. We consider three similarity measures in particular. One is the well-known cosine. The other two similarity measures have not been used before in the bibliometric literature. Finally, we show by means of an example that our findings have a high practical relevance.information science;Pearson correlation;cosine;similarity measure;author cocitation analysis
Bringing risk prevention into the bedroom : sex motives and risky behaviors in men who have sex with men
No full textWe are well into the third decade of HIV disease, and unprotected anal intercourse remains the primary mode of transmission in men who have sex with men (MSM). Since 2000, evidence suggests decreased precautionary sex behaviors and increased incidences of HIV in MSM. Traditional models of risky behaviors have focused primarily on cognitive factors related to intention to use condoms. Yet, there is an often-observed gap between intentions and behaviors. This ‘gap’ has fueled calls in the literature to move beyond cognitions and explore other psychological and contextual factors that may predict condom use. In the present study, I examined a functional model of condom use in MSM not in committed, long-term relationships, given their increased risk of HIV transmission vulnerability. Sex motives were examined as predictors of condom use in single MSM as a function of partner type and HIV serostatus. Sex motives examined were having sex to enhance intimacy, gain pleasure, escape a negative affective state, enhance self-esteem, and avoid partner disapproval. For a period of two months, MSM reported condom use for anal intercourse, sex motives, and partner type on a daily basis. Hierarchical logistic regression analyses revealed that consistent with hypotheses, on occasions when participants reported higher levels, as compared to lower levels, of having sex to enhance intimacy, and to cope with a negative affective state, the likelihood of using a condom for anal intercourse was decreased. Further, consistent with hypotheses, when participants reported higher levels, compared to lower levels, of having sex to enhance sexual pleasure, to attain partner approval, and to confirm to oneself a sense of sexual esteem, the more likely they were to use a condom for anal intercourse. Results also indicated that, in general, the relationships between motives and condom use were stronger when having sex with someone considered a regular partner as compared to casual. Finally, relationships were also stronger when participants self-reported HIV seropositive status as compared to seronegative or serostatus unknown. Implications for intervention approaches, at both the individual and community levels, are discussed.Arts, Faculty ofPsychology, Department ofGraduat
Chewing the cud, and chewing it differently : contextual and individual differences in reactive rumination and negative affect
No full textThe present study explores the relationships between reactive ruminative style,
daily reactive rumination, and daily negative affect, both within the same day, and across
days. Further, the extent to which perceived social support moderates the effect of a
reactive ruminative style on daily reactive rumination was explored. One hundred and
seventy-six individuals were interviewed and completed a structured diary twice daily for
one week. The results of hierarchical linear modeling suggested that reactive ruminative
style and daily reactive rumination interacted to predict fluctuations of daily negative
affect within the same day. Next day fluctuations in negative affect were predicted by a
reactive ruminative style. Furthermore, results indicated that perceived social support
interacted with a reactive ruminative style to predict both same day and next day daily
reactive rumination. Relevance to both reactive rumination theory and the stress and
coping literatures are discussed.Arts, Faculty ofPsychology, Department ofGraduat
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