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Jeffrey A. Woods and Brandt D. Pence

Exercise immunology is a relatively new discipline in the exercise sciences that seeks to understand how exercise affects the immune system and susceptibility to infectious and chronic diseases. This brief review will focus on three major observations that have driven the field to date including: (1) acute exercise-induced leukocytosis, (2) the observation that intense, prolonged exercise results in upper respiratory tract symptoms, and (3) the paradoxical effect of acute and chronic exercise on inflammation. This framework will be used to examine the mechanisms and implications behind these seminal observations. Data generally support the conclusion that moderate intensity exercise enhances immune function, whereas prolonged, intense exercise diminishes immune function.

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Margaret Schneider, Andrea Dunn and Daniel Cooper

Many adolescents do not meet public health recommendations for moderate-to-vigorous physical activity (MVPA). In studies of variables influencing adolescent MVPA, one that has been understudied is the affective response to exercise. We hypothesized that adolescents with a more positive affective response to acute exercise would be more active. Adolescents (N = 124; 46% male) completed two 30-min exercise tasks (above and below the ventilatory threshold [VT]), and wore ActiGraph accelerometers for 6.5 ± 0.7 days. Affective valence was assessed before, during, and after each task. A more positive affective response during exercise below the VT was associated with greater participation in MVPA (p < .05). The results are consistent with the hypothesis that individuals who have a more positive affective response to exercise will engage in more MVPA. To promote greater participation in MVPA among adolescents, programs should be designed to facilitate a positive affective experience during exercise.

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Caterina Pesce, Lucio Cereatti, Rita Casella, Carlo Baldari and Laura Capranica

This study investigated the visual attention of older expert orienteers and older adults not practicing activities with high attentional and psychomotor demands, and considered whether prolonged practice of orienteering may counteract the age-related deterioration of visual attentional performance both at rest and under acute exercise. In two discriminative reaction time experiments, performed both at rest and under submaximal physical workload, visual attention was cued by means of spatial cues of different sizes followed, at different stimulus-onset asynchronies, by compound stimuli with local and global target features. Orienteers, as compared to nonathletes, showed a faster reaction speed and a complex pattern of attentional differences depending on the time constraints of the attentional task, the demands on endogenous attentional control, and the presence or absence of a concomitant effortful motor task. Results suggest that older expert orienteers have developed attentional skills that outweigh, at least at rest, the age-related deficits of visual attentional focusing.

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Brian C. Focht and Heather A. Hausenblas

The primary purpose of the present study was to examine psychological responses of 50 young women following single episodes of aerobic exercise (AE) performed in a naturalistic exercise setting and quiet rest (QR). Given the salience of self-presentational qualities in a naturalistic exercise setting, a secondary purpose was to examine whether psychological responses to acute exercise varied as a function of social physique anxiety (SPA). The dependent measures of state anxiety, positive engagement, revitalization, tranquility, and physical exhaustion were assessed immediately prior to and then at 5 and 30 minutes following each condition. It was found that (a) AE and QR were associated with decreases in state anxiety and increases in tranquility; (b) AE was associated with increases in positive engagement and revitalization; and (c) these changes did not vary as a function of SPA level.

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Fiona Barnett

Background:

This study examined the self-efficacy and affective responses to an acute exercise bout in sedentary older and younger women to determine whether aging has an effect on affective states.

Methods:

Twenty-five sedentary younger (mean age = 19.9 yrs) and 25 older (mean age = 55.7 yrs) women completed an acute bout of exercise. Affective responses were measured before, during, and immediately following exercise. Self-efficacy responses were measured before and immediately following exercise.

Results:

Positive engagement, revitalization, tranquility, Felt Arousal and Feeling Scale responses, and self-efficacy were all higher immediately following compared with before or during exercise for both groups of women. In addition, older women experienced higher overall positive engagement and lower physical exhaustion compared with younger women as well as higher tranquility and Feeling Scale responses immediately following exercise.

Conclusions:

This investigation found that an acute bout of moderate-intensity exercise produced more positive and fewer negative affective states in both younger and older women.

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Joel B. Mitchell, James R. Rowe, Meena Shah, James J. Barbee, Austen M Watkins, Chad Stephens and Steve Simmons

To examine the effect of prior exercise on the postprandial lipid response to a high-carbohydrate meal in normal-weight (NW = BMI h25) and overweight (OW = BMI ≥25) women (age 18–25), 10 NW and 10 OW participants completed 2 conditions separated by 1 month. In the morning, the day after control (CT = no exercise) or exercise conditions (EX = 60 min cycling at 60% VO2peak), participants consumed a high-carbohydrate meal (80% CHO, 15% protein, 5% fat; 75 kJ/kg BM) followed by 6 hr of hourly blood sampling. Blood was analyzed for triglycerides (TG), blood glucose (BG), and insulin (IN). TG levels over the 6-hr period were lower in NW than OW (p = .021) and lower in EX than in CT (p = .006). Area under the curve (AUC) for TG was lower in NW than OW (p = .016) and EX than CT (p = .003). There were nonsignificant tendencies for reduced BG over time (p = .053) and AUC (p = .083), and IN AUC was lower in EX than in CT (p = .040) for both groups and lower in NW than in OW (p = .039). Prior exercise improved TG levels after a high-carbohydrate meal in both groups, and OW women demonstrated a greater postprandial lipemic response than NW regardless of condition. There were tendencies for improved glucose removal with prior exercise in NW vs. OW. Acute exercise can improve postprandial TG responses and might also improve postprandial BG and IN after a large meal in NW and OW young women.

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Daniel G. Syrotuik, Kirsten L. MacFadyen, Vicki J. Harber and Gordon J. Bell

To examine the effects of elk velvet antler supplementation (EVA) combined with training on resting and exercise-stimulated hormonal response, male (n = 25) and female (n = 21) rowers ingested either E VA (560 mg/d) or placebo (PL) during 10 wk of training. VO2max, 2000 m rowing time, leg and bench press strength were determined before and after 5 and 10 wk of training. Serum hormone levels were measured prior to and 5 and 60 min after a simulated 2000 m rowing race. VO2max and strength increased and 2000 m times decreased similarly (P < 0.05) with training. There was no significant difference between the EVA and PL group for any hormonal response. Testosterone (males only) and growth hormone (both genders) were higher 5 min after the simulated race (P < 0.05) but returned to baseline at 60 min. Cortisol was higher 5 and 60 min compared to rest (both genders) (P < 0.05) and was higher 60 min post-exercise following 5 and 10 wk of training. It appears that 10 wk of EVA supplementation does not significantly improve rowing performance nor alter hormonal responses at rest or after acute exercise than training alone.

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Xiaoya Ma, Kaitlyn J. Patterson, Kayla M. Gieschen and Peter F. Bodary

The prevalence of iron deficiency tends to be higher in athletic populations, especially among endurancetrained females. Recent studies have provided evidence that the iron-regulating hormone hepcidin is transiently increased with acute exercise and suggest that this may contribute to iron deficiency anemia in athletes. The purpose of this study was to determine whether resting serum hepcidin is significantly elevated in highly trained female distance runners compared with a low exercise control group. Due to the importance of the monocyte in the process of iron recycling, monocyte expression of hepcidin was also measured. A single fasted blood sample was collected midseason from twenty female distance runners averaging 81.9 ± 14.2 km of running per week. Ten age-, gender-, and BMI-matched low-exercise control subjects provided samples during the same period using identical collection procedures. There was no difference between the runners (RUN) and control subjects (CON) for serum hepcidin levels (p = .159). In addition, monocyte hepcidin gene expression was not different between the two groups (p = .635). Furthermore, no relationship between weekly training volume and serum hepcidin concentration was evident among the trained runners. The results suggest that hepcidin is not chronically elevated with sustained training in competitive collegiate runners. This is an important finding because the current clinical conditions that link hepcidin to anemia include a sustained elevation in serum hepcidin. Nevertheless, additional studies are needed to determine the clinical relevance of the well-documented, transient rise in hepcidin that follows acute sessions of exercise.

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Marcin Baranowski, Jan Górski, Barbara Klapcinska, Zbigniew Waskiewicz and Ewa Sadowska-Krepa

We have previously shown that acute exercise increases the level of sphingosine-1-phosphate (S1P) in plasma and ceramide in erythrocytes of untrained subjects. The aim of the current study was to examine the effect of ultramarathon run on the plasma and erythrocyte levels of the following bioactive sphingolipids: S1P, sphinganine-1-phosphate (SA1P), sphingosine, sphinganine, and ceramide. Blood samples were collected from seven male amateur runners participating in a 48-hr ultramarathon race before the run, after 24 and 48 hr of running, and following 24 and 48 hr of recovery. The sphingolipids were quantified by means of HPLC. Sustained running for 48 hr resulted in a progressive decline in plasma S1P to a level significantly lower than at prerace, and then remained stable over the next 48 hr of recovery. In erythrocytes, S1P content was stable until 24 hr of recovery, then rose abruptly to reach peak values after 48 hr of recovery. The plasma level of SA1P decreased progressively during the competition and remained unchanged over the recovery. In erythrocytes, the level of SA1P increased after 24 hr running and normalized thereafter. The level of ceramide, both in plasma and erythrocytes, was not significantly affected by the ultraendurance run. We speculate that reduction in plasma level of S1P during and after the run reduces its biological actions and might be responsible for some negative side-effects of the ultraendurance effort.

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Jonathan M. Peake

Ascorbic acid or vitamin C is involved in a number of biochemical pathways that are important to exercise metabolism and the health of exercising individuals. This review reports the results of studies investigating the requirement for vitamin C with exercise on the basis of dietary vitamin C intakes, the response to supplementation and alterations in plasma, serum, and leukocyte ascorbic acid concentration following both acute exercise and regular training. The possible physiological significance of changes in ascorbic acid with exercise is also addressed. Exercise generally causes a transient increase in circulating ascorbic acid in the hours following exercise, but a decline below pre-exercise levels occurs in the days after prolonged exercise. These changes could be associated with increased exercise-induced oxidative stress. On the basis of alterations in the concentration of ascorbic acid within the blood, it remains unclear if regular exercise increases the metabolism of vitamin C. However, the similar dietary intakes and responses to supplementation between athletes and nonathletes suggest that regular exercise does not increase the requirement for vitamin C in athletes. Two novel hypotheses are put forward to explain recent findings of attenuated levels of cortisol postexercise following supplementation with high doses of vitamin C.