Use this URL to cite or link to this record in EThOS: https://ethos.bl.uk/OrderDetails.do?uin=uk.bl.ethos.821258
Title: The influence of vitamin D, psychosocial factors and sleep on upper respiratory tract infection and mucosal immunity
Author: Harrison, Sophie
Awarding Body: Bangor University
Current Institution: Bangor University
Date of Award: 2020
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Abstract:
The broad aims of this thesis were to investigate the influence of vitamin D supplementation on URTI burden in military recruits (Chapter 3), to examine the influence of psychosocial and behavioural factors on URTI risk in marathon runners (Chapter 4), and to investigate the influence of psychological stress and anxiety on the mucosal immune response to exercise, in both a controlled, lab-based setting and a field-based marathon (Chapter 5). Firstly, we found that vitamin D sufficiency lowered URTI burden in military recruits during Army training (Chapter 3). Specifically, in 1,644 military recruits, we found that vitamin D sufficient recruits were less likely to have a clinician-diagnosed URTI during training, compared to those with serum 25(OH)D < 50 nmol·L-1(Study 1). Then, in a randomised-control-trial (RCT), including 249 men, we found that vitamin D supplementation by oral D3 or simulated sunlight, which achieved vitamin D sufficiency in almost all, reduced URTI burden regardless of supplementation type: 21% lower URTI peak severity and 36% fewer days with URTI (Study 2). And that individuals beginning supplementation with 25(OH)D < 50 nmol·L-1 benefitted from greater reductions in URTI burden: 33% shorter URTI duration. However, we did not find any influence of vitamin D supplementation on mucosal immunity. In Chapter 4, a prospective, cohort study of 305 marathon runners, we examined the influence of psychosocial factors and sleep on URTI prevalence. We found that runners were more likely to report a URTI during the two weeks before or after a marathon if they reported higher psychological stress, anxiety or neuroticism, early life adverse experience, or lower perceived sleep quality. Runners with early life adverse experience were over two times more likely to report a URTI during the two weeks before the marathon (OR: 2.33) and runners with poorer perceived sleep quality were two times more likely to report a URTI during the two weeks after the marathon (OR: 0.48). In the final empirical chapter, we examined the influence of psychological stress and anxiety on the mucosal immune response to a moderate, lab-based bout of exercise (Study 1) and a field-based marathon (Study 2; Chapter 5). We found that perceived psychological stress, trait anxiety and state anxiety influenced the mucosal immune response to exercise. In men, perceived psychological stress, trait anxiety and state anxiety were negatively correlated with the mucosal immune response to exercise. In response to a controlled, moderate bout of exercise, in individuals with predominantly low-moderate psychological stress and anxiety, men with lower psychological stress and anxiety experienced an increase in saliva SIgA SR, whereas those with moderate stress and anxiety saw little change. Then, in a field-based marathon, when including individuals reporting high stress and anxiety, men with higher perceived psychological stress and trait anxiety had a greater reduction in mucosal immunity in response to a marathon. These findings support the recommendation that exercise physiologists should account for psychological stress and anxiety when examining the immune response to exercise. Taken together, Chapters 4 and 5 indicate a key role of psychological factors in immunity in exercising individuals. Specifically, individuals with higher psychological stress and anxiety appear to be at greater risk of URTI and experience greater reduction in mucosal immunity following exercise.
Supervisor: Roberts, Ross Sponsor: Not available
Qualification Name: Thesis (Ph.D.) Qualification Level: Doctoral
EThOS ID: uk.bl.ethos.821258  DOI: Not available
Keywords: Exercise ; Sport ; Health ; Immunology ; Mucosal immunity ; Common cold ; Respiratory Infection ; Vitamin D ; Psychological stress ; Anxiety ; Sleep ; Early life adversity ; Adverse childhood experiences ; Military
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