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Gary J. Walker, Phillipa Caudwell, Natalie Dixon, and Nicolette C. Bishop

This study investigated the effect of caffeine ingestion on neutrophil oxidative burst responses to prolonged cycling. In a two part study, 19 endurance trained male cyclists (Part A – 11; Part B – 8) performed 90 min of exercise at 70% VO2max 1 h after ingesting 6 mg/kg body mass of caffeine (CAF) or placebo (PLA). CAF ingestion had no effect on the PMA-stimulated oxidative burst response (Part A), yet it attenuated the exercise-induced decline in f-MLP stimulated response that occurred with PLA (Part B). CAF ingestion significantly increased serum caffeine concentration and plasma adrenaline concentration following exercise. In addition, circulating lymphocyte count was increased following CAF ingestion whereas there was no effect on neutrophil number. Therefore, although CAF ingestion was associated with an increase in adrenaline, this was not associated with an expected decrease in neutrophil function. This suggests that in the present study, CAF ingestion influenced neutrophil function via alternative mechanisms.

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Laura E. Juliff, Jeremiah J. Peiffer, and Shona L. Halson

periods of sleep and wakefulness. 8 Athletic competitions have the ability to stimulate neurotransmitters (adrenaline and noradrenaline) of the ascending arousal system, triggering the release of cortisol and potentially causing a disruption of the sleep–wake cycle. 9 Indeed, within patients with

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Pedro Tauler, Sonia Martinez, Pau Martinez, Leticia Lozano, Carlos Moreno, and Antoni Aguiló

This study compared the response of interleukin (IL)-10, and also of IL-6 and IL-12 p40, to exercise and caffeine supplementation between plasma and blood mononuclear cells (BMNCs). Participants in the study (n = 28) were randomly allocated in a double-blind fashion to either caffeine (n = 14) or placebo (n = 14) treatments. One hour before completing a 15-km run competition, athletes took 6 mg/kg body mass of caffeine or a placebo. Plasma and BMNCs were purified from blood samples taken before and after competition. Concentrations of interleukins (IL-10, IL-6, and IL-12 p40), cyclic adenosine monophosphate (cAMP), caffeine, adrenaline, and cortisol were measured in plasma. IL-10, IL-6, and IL-12 p40 and cAMP levels were also determined in BMNCs. Exercise induced significant increases in IL-6 and IL-10 plasma levels, with higher increases in the caffeine-supplemented group. After 2-hr recovery, these levels returned to almost preexercise values. However, no effect of caffeine on BMNC cytokines was observed. IL-10, IL-6, and IL-12 p40 levels in BMNCs increased mainly at 2 hr postexercise. cAMP levels increased postexercise in plasma and after recovery in BMNCs, but no effects of caffeine were observed. In conclusion, caffeine did not modify cytokine levels in BMNCs in response to exercise. However, higher increases of IL-10 were observed in plasma after exercise in the supplemented participants, which could suppose an enhancement of the anti-inflammatory properties of exercise.

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Jozef Langfort, Ryszard Zarzeczny, Krystyna Nazar, and Hanna Kaciuba-Uscilko

The purpose of this study was to discover whether severe dietary carbohydrate (CHO) restriction modifies the relationship between exercise intensity and hormonal responses to exercise. Changes in the plasma adrenaline (A), noradrenaline (NA), growth hormone (hGH), testosterone (T), and blood lactate (LA) during an incremental exercise performed until volitional exhaustion were determined in 8 physically active volunteers after 3 days on low CHO (<5% of energy content; L-CHO) and isocaloric mixed (M) diets. Following L-CHO diet, the basal plasma A, NA, and hGH concentrations were increased, whilst T and LA levels were decreased. During exercise all the hormones increased exponentially, with thresholds close to that of LA. Neither the magnitude nor the pattern of the hormonal changes were affected by L-CHO diet except the NA threshold, which was lowered. Blood LA response to exercise was diminished and LA threshold was shifted towards higher loads by L-CHO diet. It is concluded that restriction of CHO intake (a) does not affect the pattern of changes in plasma A, hGH, and T concentrations during graded exercise but lowers NA threshold, indicating increased sensitivity of the sympathetic nervous system to exercise stimulus; (b) alters the basal and exercise levels of circulating hormones, which may have an impact on the balance between anabolic and catabolic processes and subsequently influence the effectiveness of training.

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Maïtel Botcazou, Christophe Jacob, Arlette Gratas-Delamarche, Sophie Vincent, Danièle Bentué-Ferrer, Paul Delamarche, and Hassane Zouhal

The purpose of this study was to clarify the effect of sex on plasma catecholamine responses to sprint exercise in adolescents and adults. Thirty-six untrained participants took part in this study—9 girls and 10 boys (Tanner Stage 4) and 9 women and 8 men. Each participant performed a 6-s sprint test on a cycle ergometer. Plasma adrenaline (A) and noradrenaline (NA) concentrations were determined successively at rest (A0 and NA0), immediately after the 6-s sprint test (AEX and NAEX), and after 5 min of recovery (A5 and NA5). Peak power, expressed in absolute values or relative to body weight and fat-free mass, was significantly higher in boys than in girls and higher in men than in women (p < .001). No sex effect was observed in AEX in the adolescents, but the NA increase was significantly higher in boys in response to the 6-s sprint (p < .05). In adults, no sex difference was found in NAEX, but AEX was significantly higher in men than in women (p < .05). NAEX was significantly higher in women than in girls (p < .05), and AEX was significantly higher in men than in boys (p < .01). The results of this study suggest that male and female adolescents and young adults might exhibit different catecholamine responses to sprint exercise.

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Carly Litchfield, Denise M. Connelly, Melissa E. Hay, and Elizabeth Anne Kinsella

, and your legs making those turns. Many participants described the feeling of skiing at high velocities. For instance, Nancy conveyed: “ … that feeling of being fast, flying down the hill, is to me the best feeling; the adrenaline, the speed: it results in this feeling, well like you are flying!” The

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-6 and IL-10, to an acute bout of exercise. The aim of this study was to determine whether adrenaline, cortisol or cyclic adenosine monophosphate (cAMP) mediate this effect. In a randomized, crossover, double-blind study, thirteen healthy, well-trained amateur male athletes performed a treadmill

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Ed Maunder, Deborah K. Dulson, and David M. Shaw

physiological stress associated with the dramatic dietary shift during the initial stages of adaptation to a KD may inhibit exercise performance in some individuals when assessed a few weeks later. For example, a 3-day KD in untrained humans increased resting plasma adrenaline, noradrenaline, and cortisol

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John Stoszkowski and Hans Amato

stress hormones (e.g., glucagon, cortisol, and adrenaline) become elevated, and the production of thyroid hormone (and the conversion of T4 to T3) is reduced ( DeGroot, 2015 ), which can manifest in a raft of physical and mental issues. For example, hypothyroidism is associated with mood disturbances

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Lauren Anne Lipker, Caitlyn Rae Persinger, Bradley Steven Michalko, and Christopher J. Durall

adrenaline and growth hormone and may reveal the underlying atrophy-attenuating effect from BFR. 1 In addition, when exercising muscle is exposed to a hypoxic environment, as was the case in 2 of the reviewed studies, the type I muscle fibers that require large amounts of oxygen for contraction cannot