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Helen G. Hanstock, Andrew D. Govus, Thomas B. Stenqvist, Anna K. Melin, Øystein Sylta and Monica K. Torstveit

HIT (4 × 4 min) , despite lower heart rates (HRs), blood lactate concentrations, ratings of perceived exertion (RPE), and a less pronounced steroid hormone response. 3 However, it is unclear how different interval training prescriptions influence athletes’ health and immune status. Training

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Andres E. Carrillo, René J. L. Murphy and Stephen S. Cheung

Purpose:

Prolonged physical exertion and environmental heat stress may elicit postexercise depression of immune cell function, increasing upper respiratory tract infection (URTI) susceptibility. We investigated the effects of acute and short-term vitamin C (VC) compared with placebo (PL) supplementation on URTI susceptibility, salivary immunoglobulin A (s-IgA), and cortisol responses in healthy individuals following prolonged exercise-heat stress.

Methods:

Twelve participants were randomized into the VC or PL group in a double-blind design. For 12 days, participants consumed 3 × 500 mg tablets of VC or PL per day, with testing completed at baseline, then following acute (1 d) and short-term (8 d) supplementation. Participants performed 120.1 ± 49.6 min of cycling at 54 ± 6% VO2max in a hot (34.8 ± 1.0°C and 13 ± 3% relative humidity) environment, with saliva samples collected at pre-, post-, and 72 h postexercise. Health logs specifying URTI symptoms were completed for 7 days postexercise.

Results:

A 2 × 3 × 3 mixed ANOVA with a post hoc Bonferroni correction factor revealed a significant linear trend in postexercise cortisol attenuation in the VC group, 21.7 ± 15.1 nmol/L (mean ± SD) at baseline, to 13.5 ± 10.0 at acute, to 7.6 ± 4.2 after short term (P = .032). No differences were detected in ratio of s-IgA to protein or URTI symptoms between groups.

Conclusions:

These data suggest that vitamin C supplementation can decrease postexercise cortisol in individuals performing exercise similar to that of a half-marathon or marathon in hot conditions. However, no changes in s-IgA and URTI were evident, possibly due to previous moderate training and reduced physical and psychological stress compared with athletes participating in ultramarathons.

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Lindy M. Castell, David C. Nieman, Stéphane Bermon and Peter Peeling

Immunodepression and Immunonutrition Investigation of exercise-induced effects on the immune system began more than 100 years ago, when Larrabee ( 1902 ) observed a marked leukocytosis after violent exercise, including a large number of polymorphonuclear neutrophils. Since then, many scientists

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Dru A. Henson, David C. Nieman, Andy D. Blodgett, Diane E. Butterworth, Alan Utter, J. Mark Davis, Gerald Sonnenfeld, Darla S. Morton, Omar R. Fagoaga and Sandra L. Nehlsen-Cannarella

The influence of exercise mode and 6% carbohydrate (C) versus placebo (P) beverage ingestion on lymphocyte proliferation, natural killer cell cytotoxicily (NKCA), Interleukin (IL)-1ß production, and hormonal responses to 2.5 hr of intense running and cycling (~75% V˙O2max) was measured in 10 triathletes serving as their own controls. The C versus P condition (but not exercise mode) resulted in higher plasma glucose concentrations, lower plasma cortisol concentrations, reduced poslexercise lymphocytosis and NKCA, and a lessened T-cell reduction during recovery. No condition or mode effects were observed for concanavalin A and phytohemagglutinin-induced lymphocyte proliferation. Significant mode (but not condition) effects were observed for lipopolysaccharide-induced IL-1ß production over time. However, when expressed per monocyte, the mode effect was abolished and a sustained suppression in IL-1 ß/monocyte was observed in all sessions throughout recovery. These data indicate that carbohydrate ingestion significantly affects plasma glucose and cortisol concentrations, blood lymphocyte counts, and NKCA, whereas exercise mode has no effect on these parameters.

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Alannah K. A. McKay, Ida A. Heikura, Louise M. Burke, Peter Peeling, David B. Pyne, Rachel P.L. van Swelm, Coby M. Laarakkers and Gregory R. Cox

). Despite the potential long-term implications to athlete health and performance, studies exploring these effects in elite athletes are lacking. Therefore, we quantified the effect of a sleep-low protocol in the daily training environment on markers of inflammation, iron regulation, and immune function in

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Shlomit Radom-Aizik

Two papers were selected for this commentary. The first paper (Citation 1) suggests that a 10-week, moderate-intensity exercise program performed early after allogeneic hematopoietic stem cell transplantation is feasible in this fragile population, and might improve cell cytotoxicity by redistributing subpopulations of NK cells. This study adds to the growing evidence that enhancing immune cell surveillance (e.g., NK cells) in response to exercise could benefit cancer patients. The second paper (Citation 2) studied neutrophil-related mediators of oxidative stress and inflammatory cytokines in response to exercise in children compared with adults. The authors found age/maturation-related differences in these responses. The paper provides a valuable introduction to the current knowledge of maturational changes in immune mediators’ response to exercise. Data about leukocyte function in response to exercise in healthy children and in children with clinical conditions is scant. The need for prospective large scale pediatric clinical exercise studies is clear. Molecular approaches to understand the mechanisms through which physical activity can improve health will help to shape guidelines that optimize the mode, frequency, intensity, and duration of the training intervention.

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Brian W. Timmons

Despite significant advances in exercise immunology over the last two decades, our understanding of immune responses to exercise in children remains sparse. This review outlines and discusses commonly reported aspects of the immune response to exercise, with emphasis on child-adult differences. Compared with adults, children generally experience smaller perturbations to the immune system (e.g., NK cells and IL-6) in response to exercise of the same duration and intensity. Children also demonstrate a faster recovery of immune components (e.g., neutrophil and IL-6) after exercise. The health and clinical relevance of exercise-induced changes in a child’s immune system remain to be determined.

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Bindu P. Gopalan, Mary Dias, Karthika Arumugam, Reena R. D’Souza, Mathew Perumpil, Prasanna Kulkarni, Udaykumar Ranga and Anita Shet

neuropsychiatric disorders ( 28 ). The pathogenesis of these illnesses is attributable to the accelerated aging and immune senescence due to chronic inflammation and immune activation ( 17 ) resulting from the direct effect of HIV, microbial translocation, coinfections, and other comorbidities ( 19 ). To reduce

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Tom Clifford, Eleanor J. Hayes, Jadine H. Scragg, Guy Taylor, Kieran Smith, Kelly A. Bowden Davies and Emma J. Stevenson

/or satellite cell activation, possibly driven by immune senescence or “inflammageing,” the age-related phenomenon characterized by a persistent elevation in systemic immune markers, such as interleukin-6 (IL-6) and C-reactive protein ( Calder et al., 2017 ; Doering et al., 2017 ; Doering, Reaburn, et

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William A. Braun, Michael G. Flynn, Daniel L. Carl, Kathy K. Carroll, Todd Brickman and Charlie P. Lambert

Iron deficiency may lead to anemia and may result in compromised endurance exercise performance. Iron deficiency has also been reported to adversely affect the immune system and has been associated with attenuation of natural killer cell (NK) activity. This study was conducted to examine the relationship between iron status and NK activity in highly conditioned female athletes. Ten collegiate female swimmers (SWM) and 9 inactive females (SED) participated in this investigation. Resting blood samples were obtained and analyzed for serum iron and ferritin. NK activity (% lysis) was determined using a whole blood method (51Cr release assay). No significant relationship was found between iron and NK activity (r = 0.55, p = .09), nor between serum ferritin and NK activity (r = 0.33. p = .35) for SWM. ANOVA revealed significantly greater NK activity for SWM (51.63 ± 15.79%) versus SED (30.34 ± 13.67%). Serum ferritin levels were not significantly different between SWM (20.38±8.62Ƞg · ml−1) and SED (16.79±10.53Ƞg · ml−1), nor were iron values different between groups (16.54 ± 2.17 μmol · L−1 SWM; 11.92 ± 2.61 μmol · L−1 SED). A significant relationship between iron status and resting immune function could not be established. Exercise training may affect NK activity; however, the influence of iron status on immune function requires further evaluation.