109 research outputs found
Acute and chronic effects of exercise on markers of mucosal immunity
Decreased secretion rate of salivary markers of mucosal immunity, and in particular salivary immunoglobulin A (s-
IgA), have been implicated as risk factors for subsequent episodes of respiratory infection in athletes. IgA is the predominant Ig
in mucosal secretions and acts with innate mucosal defences to provide the ‘first line of defence’ against pathogens and antigens
presented at the mucosa. As well as summarising the evidence concerning the effects of acute exercise and longer-term intensive
training on these markers of mucosal immunity, this review explores the factors that impact upon salivary responses to exercise,
such as method of saliva collection, stimulation of saliva collection and the method of reporting s-IgA data. The influence of
adequate hydration and nutritional supplementation during exercise as well as exercising in extreme environmental conditions on
salivary responses is also explored. Finally, the possible mechanisms underlying the acute and longer-term of effects of exercise
on salivary responses are examined, with particular emphasis on the potential role of the sympathetic nervous system and the
expression and mobilisation of the polymeric Ig receptor
Effect of a single and repeated dose of caffeine on antigen-stimulated human natural killer cell CD69 expression after high-intensity intermittent exercise
Several studies investigating the effect of caffeine on immune function following exercise have used one large bolus dose of caffeine. However, this does not model typical caffeine consumption. Therefore, the purpose of this study was to investigate whether small repeated doses of caffeine ingested throughout the day would elicit a similar response as one large bolus dose ingested 1 h prior to exercise on antigen-stimulated NK cell CD69 expression following strenuous intermittent exercise. In a randomized cross-over design, 15 healthy males completed six 15 min blocks of intermittent running consisting of maximal sprinting interspersed with less intense running and walking. Participants had ingested either 0 (PLA), 2 mg kg−1 body mass (BM) caffeine on three separate occasions during the day (3× CAF) or one dose of 6 (1× CAF) mg kg−1 BM caffeine, 1 h before exercise. At 1-h post-exercise, the number of antigen-stimulated CD3−CD56+ cells expressing CD69 was lower on 1× CAF compared with PLA [P < 0.05; PLA: 42.0 (34.0) × 106 cells L−1, 1× CAF: 26.2 (25.0) × 106 cells L−1], with values on 1× CAF at this time point remaining close to pre-supplement. 1× CAF tended to attenuate the exercise-induced increase in geometric mean fluorescence intensity of CD69 expression on antigen-stimulated CD3−CD56+ cells 1-h post-exercise [P = 0.055; PLA: 141 (28)%, 1× CAF: 119 (20)%]. These findings suggest that although one large bolus dose of caffeine attenuated the exercise-induced increase in antigen-stimulated NK cell CD69 expression 1 h following strenuous intermittent exercise, this attenuation at no point fell below pre-supplement values and caffeine does not appear to depress NK cell CD69 expression
Effect of a high and low dose of caffeine on human lymphocyte activation in response to antigen stimulation
This study investigated the effect of caffeine on antigen-stimulated lymphocyte activation. Six males rested for 3.5 h
after ingesting 0 (PLA), 2, or 6 (6CAF) mg·kg−1 body mass of caffeine. The number of antigen-stimulated NK CD69+ cells increased
in 6CAF at 1 h compared with PLA (P = 0.021). Caffeine did not influence the number of antigen-stimulated CD69+ T cells or the
geometric mean fluorescence intensity expression of CD69 on antigen-stimulated lymphocytes, suggesting caffeine has little
effect on antigen-stimulated lymphocyte activation
Effects of Lactobacillus casei Shirota ingestion on common cold infection and herpes virus antibodies in endurance athletes: a placebo-controlled, randomized trial
Aims To assess evidence of health and immune benefit by
consumption of a Lactobacillus casei Shirota probiotic in
highly physically active people.
Methods Single-centre, population-based, randomized,
double-blind, placebo-controlled trial. Daily ingestion of
probiotic (PRO) or placebo (PLA) for 20 weeks for n = 243
(126 PRO, 117 PLA) university athletes and games players.
Subjects completed validated questionnaires on upper respiratory
tract infection symptoms (URS) on a daily basis
and on physical activity status at weekly intervals during
the intervention period. Blood samples were collected
before and after 20 weeks of the intervention for determination
of Epstein Barr virus (EBV) and cytomegalovirus
(CMV) serostatus and antibody levels.
Results URS episode incidence was unexpectedly low
(mean 0.6 per individual) and was not significantly different
on PRO compared with PLA. URS episode duration
and severity were also not influenced by PRO. A significant
time × group interaction effect was observed for plasma
CMV antibody titres in CMV seropositive participants
(p < 0.01) with antibody titre falling in the PRO group
but remaining unchanged in the PLA group over time. A
similar effect was found for plasma EBV antibody titres in
EBV seropositive participants (p < 0.01) with antibody titre
falling in the PRO group but increasing in the PLA group
over time. Conclusions In summary, regular ingestion of PRO did not
reduce URS episode incidence which might be attributable
to the low URS incidence in this study. Regular ingestion
of PRO reduced plasma CMV and EBV antibody titres, an
effect that can be interpreted as a benefit to overall immune
status
Exercise intensity and its impact on relationships between salivary immunoglobulin A, saliva flow rate and plasma cortisol concentration
Introduction Salivary secretory immunoglobulin A (sIgA), saliva flow rate and plasma cortisol concentrations have been shown to be influenced by exercise, particularly the intensity exercise is performed at, and circadian variation. The autonomic nervous system partly regulates salivary secretion, but it is not yet known whether cortisol also explains some variation in salivary parameters.
Methods Twelve moderately trained male individuals (V̇ O2peak legs: 46.2±6.8 mL·kg−1·min−1) performed three 45-min constant load exercise trials in the morning: arm cranking exercise at 60%V̇ O2peak arms; moderate cycling at 60%V̇ O2peak legs; and easy cycling at 60%V̇ O2peak arms. Timed saliva samples and blood samples for plasma cortisol concentration determination were obtained before, post, 2 h post, and 4 h post-exercise. Saliva was collected in an additional resting trial at the same time points.
Results At each time point for each exercise trial, negative correlations between cortisol and saliva flow rate (explaining 25±17% of the variance, R2=0.002–0.46) and positive correlations between cortisol and sIgA concentration (explaining 8±8% of the variance R2=0.002–0.24) were found. Saliva flow rate increased over time, whereas sIgA concentration and cortisol decreased over time for all trials (P<0.05), there was no effect of time for sIgA secretion rate (P=0.16).
Conclusion These results show a relationship between cortisol and saliva flow rate, which directly impacts on the concentration of salivary analytes. This study further confirms circadian variations in salivary parameters which must be acknowledged when standardising salivary data collection
Effects of exercise and sport in solid organ transplant recipients: a review
Solid organ transplantation is the gold-standard treatment for many with end-organ failure and can offer a new independence from the burden of disease. However solid organ transplant recipients (SOTRs) remain at high risk of cardiovascular disease (CVD), poor quality of life and physical functioning. Increasing physical activity and exercise can improve the health of the general population, however the effects on those with a transplant remain unclear. Intensive exercise and sporting activity has the potential to be beneficial, although there remain concerns particularly around the effects on immune function and the CV system. This review summarises what is known about the effects of exercise on determinants of health in SOTR and then collates the available literature investigating the consequences of intensive exercise and sport on the health of SOTR. There is a paucity of high-quality research, with most evidence being case-studies or anecdotal; this is understandable given the relatively few numbers of SOTR who are performing sport and exercise at a high level. However if suitable evidence-based guidelines are to be formed and SOTR are to be given reassurances that their activity levels are not detrimental to their transplanted organ and overall health, then more high-quality studies are required
Can intervals enhance the inflammatory response and enjoyment in upper-body exercise?
Purpose
To investigate the inflammatory and perceptual responses to three different forms of upper-body exercise.
Methods
Twelve recreationally active, able-bodied males performed three work-matched arm-crank sessions in a randomised order: 30 min moderate-intensity continuous (CON), 30 min moderate-intensity with changes in cadence (CAD) and 20 min high-intensity interval training (HIIT). Blood samples were taken pre, post and 2-h post-exercise to determine plasma concentrations of interleukin (IL)-6 and IL-1ra. Perceptual responses pre, during and following the trials were assessed using the Feeling Scale, Felt Arousal Scale, Ratings of Perceived Exertion (RPE) and the Physical Activity Enjoyment Scale (PACES).
Results
All trials were evenly effective in inducing an acute inflammatory response, indicated by similar increases in IL-6 after exercise and in IL-1ra at 2-h post exercise for all trials. More negative affect and higher RPE were reported during HIIT compared to CON and CAD, whereas PACES scores reported after exercise were higher for HIIT and CAD compared to CON.
Conclusions
When matched for external work, there was no difference in the inflammatory response to HIIT compared to moderate-intensity upper-body exercise. Although HIIT was (perceived as) more strenuous and affective responses were more negative during this mode, the higher ratings of enjoyment for both HIIT and CAD reported after exercise suggest that the inclusion of variation enhances enjoyment in upper-body exercise. As the fashion in which upper-body exercise is performed does not seem to influence the inflammatory response, it might be advised to prescribe varied exercise to enhance its enjoyment
Spinal cord injury: known and possible influences on the immune response to exercise
A spinal cord injury (SCI) can increase the risk of infection by impacting on
many aspects of immune function; one particularly well-documented observation
is a reduction in lymphocyte numbers. The vast majority of lymphoid cells
express adrenergic receptors. Therefore, autonomic function loss and concomitant
alterations in resting and post-exercise catecholamine concentrations, particularly
so in individuals with a tetraplegia, may impact directly on immune cells and
depress immunity. Other factors are further likely to contribute, examples including
altered muscular, endocrine and cardiovascular function following SCI. However,
some alterations, such as increases in natural killer cell cytotoxicity following
exercise in those with a tetraplegia, are unrelated to the catecholamine
response. Likewise, mucosal immunity in individuals with a tetraplegia appears to
be similarly influenced by exercise as in the able-bodied population. Indeed, rehabilitation
therapy and exercise can increase some measures of immunity and autonomic
function in those with an SCI. It is therefore possible that compensatory
mechanisms offset disability-related detriments. This may be by way of sympathetic
reflex activity, receptor hypersensitivity, or parasympathetic and neuroendocrine
adjustments. Future work needs to explore these mechanisms further to
clarify the implications of an SCI on the immune response to exercise and susceptibility
to infection. In this article, we review the impacts of an SCI on immune, and specifically, exercise
immune function. The relevant anatomical and physiological foundations of
the immune system are first briefly laid out in order to understand the potential
impacts of neural and neuroendocrine dysfunction on the immune system. With
the limited number of human studies available, we have then aimed specifically to
gather all relevant existing literature on exercise immunology in individuals with
an SCI in patient, recreationally active and athlete populations. We believe that an
understanding of the impacts of exercise can provide a tool to help maintain or
improve health in individuals with an SCI
Daily probiotic's (lactobacillus casei shirota) reduction of infection incidence in athletes
The purpose of this study was to examine the effects of a probiotic supplement during 4 mo of winter training in men and women engaged in endurance-based physical activities on incidence of upper respiratory-tract infections (URTIs) and immune markers. Eighty-four highly active individuals were randomized to probiotic (n = 42) or placebo (n = 42) groups and, under double-blind procedures, received probiotic (PRO: Lactobacillus casei Shirota [LcS]) or placebo (PLA) daily for 16 wk. Resting blood and saliva samples were collected at baseline and after 8 and 16 wk. Weekly training and illness logs were kept. Fifty-eight subjects completed the study (n = 32 PRO, n = 26 PLA). The proportion of subjects on PLA who experienced 1 or more weeks with URTI symptoms was 36% higher than those on PRO (PLA 0.90, PRO 0.66; p = .021). The number of URTI episodes was significantly higher (p < .01) in the PLA group (2.1 ± 1.2) than in the PRO group (1.2 ± 1.0). Severity and duration of symptoms were not significantly different between treatments. Saliva IgA concentration was higher on PRO than PLA, significant treatment effect F(1, 54) = 5.1, p = .03; this difference was not evident at baseline but was significant after 8 and 16 wk of supplementation. Regular ingestion of LcS appears to be beneficial in reducing the frequency of URTI in an athletic cohort, which may be related to better maintenance of saliva IgA levels during a winter period of training and competition
Plasma cytokine and exertional responses in relation to exercise intensity and volume of exercising muscle mass during arm-crank ergometry
Plasma cytokine and exertional responses in relation to exercise intensity and volume of exercising muscle mass during arm-crank ergometr
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