Introduction: A single exercise training session promotes stimuli for changes in the immune system that are cumulatively considered adaptations to the exercise. Objective: This paper explores the acute effect of different intensities of aerobic exercise on anti-inflammatory and proinflammatory markers in apparently healthy university students. Methods: Eighteen volunteers underwent two sessions of aerobic exercise, the first at 65-70% estimated heart rate (HR), and after seven days, a second session at 80-85% HR. Before and after each session, venous blood was drawn, in order to analyze interleukin (IL) 6 and 10 in a Milliplex Kit. The participants’ level of physical activity was determined using a questionnaire. For statistical comparisons, two-way ANOVA was used for the variables hemodynamics and perceived exertion. The cytokine results were compared through the Student's t-test for repeated measurements. The exclusion criteria were the practice of physical exercise and having drunk alcohol on the day before the intervention sessions, the presence of osteomioarticular conditions, and missing one of the sessions. Results: This study showed that IL-6 was not significantly decreased when comparing the two sessions. IL-10 was significantly decreased (p=0.033) in the 65-70% HR session but not in the 80-85% HR session. The delta variation for IL-10 showed a tendency (p=0.053) towards a greater decrease in the 65-70% HR session when compared to the 80-85% HR session. There were no differences in the acute effect of exercise when comparing the levels of physical activity. Conclusion: This study highlights that two different zones of high intensity exercise can induce different inflammatory responses, as demonstrated by the significant decrease in IL-10 in the 65-70%HR zone. The study also shows that there was no difference in physical exercise response in individuals with moderate and high physical activity levels. Level of evidence III; Comparative study.

The aim of this study was to investigate whether the use of handrail support during maximal exercise treadmill testing (ETT) would interfere in cardiac autonomic modulation kinetics when compared to not using handrail support. The hypothesis of overestimation in cardiac autonomic dynamics when the ETT is performed using handrail was tested. Thirty-five undergraduates (21.08 ± 2.98 years old) of both sexes, volunteered to undertake two ETT under the Ellestad protocol, in non-consecutive days. The first test (T1) was performed with handrail support and, after 7 days, the second test was performed (T2) without the support. Autonomic function was measured by heart rate variability (HRV) during both tests and resting. Estimated value of peak oxygen uptake (VO2) was 22.4% (p < 0.0001) higher in T1 when compared to T2. Overall, parasympathetic pathway was deactivated earlier in T2 than in T1, with NNxx measures variating in T1 from 10.74 ± 14.59 (ms) and in T2 from 3.48 ± 3.79 (ms). In stage two, mean values of HF in T2 corresponded to 32% of values in T1. Stage three presented a difference of 60% (p < 0.014) in LF between means reached in T1 and T2. Lastly, the association of LF and VO2 persisted longer in T1 stages than in T2 and was verified in early stages (S2 and S3) of both ETTs. Our findings suggest that parasympathetic influences on HR were slightly prolonged during ETT when subjects hold onto the treadmill.

O exercício físico gera um desvio da homeostase e a reorganização das respostas de diversos sistemas, entre eles o sistema imune. A resposta aguda do sistema imune pode estar sujeita a mudanças de acordo com a intensidade do exercício praticado. O objetivo do estudo é observar a resposta da proliferação linfocitária à prática de sessões de exercício físico aeróbio de diferentes intensidades. Para tal, foram avaliados dez voluntários (23,50 ± 3,43 anos), que realizaram sessões de exercício aeróbio em bicicleta indoor nas intensidades moderada (40-59% da frequência cardíaca de reserva - FCr) e vigorosa (60-89% da FCr). Houve coleta de sangue venoso para análise da proliferação linfocitária antes (baseline) e após cada uma das sessões. A proliferação linfocitária foi estimulada através de Concanavalina A e mensurada através do ensaio de Alamar Blue® por análise fluorimétrica após 24h, 48h e 72h de cultivo. A análise estatística compreendeu comparações repetidas entre as diferentes sessões e o baseline por ANOVA two-way, considerando um p < 0,05. A sessão de exercício de intensidade vigorosa apresentou diminuição significativa da proliferação linfocitária basal de 21,96% (p = 0,011) em 24h, 37,46% (p = 0,001) em 48h e 27,61% (p = 0,005) em 72h quando comparada com o baseline. A sessão de exercício de intensidade moderada mostrou um aumento de 42,17% (p = 0,001), 36,89% (p = 0,011) e 30,84% (p = 0,001) para os mesmos tempos. Houve diferença significativa no delta de variação na comparação entre as intensidades (p < 0,005). A prática aguda de exercício físico aeróbio em intensidades moderada e vigorosa foi associada ao aumento e diminuição, respectivamente, da proliferação linfocitária de adultos.

An amendment to this paper has been published and can be accessed via a link at the top of the paper.

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