Author Correction: Handrail support interference in cardiac autonomic modulation adjustments in young adults during maximal exercise testing.

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

Handrail support interference in cardiac autonomic modulation adjustments in young adults during maximal exercise testing.

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.

Efeito agudo do exercício físico aeróbio de diferentes intensidades na proliferação linfocitária de adultos / Acute effect of aerobic exercise training of different intensities on lymphocyte proliferation in adults

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 vigo-rosa (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.

Physical exercise causes a deviation in homeostasis and the reorganization of various systems responses, including the immune system. The acute response of the immune system may differ according to the intensity of physical exercise. The objective of this study is to analyze the lymphocyte proliferative response to the practice of aerobic physical exercise sessions of varying intensities. Ten volunteers (23.50 ± 3.43 years) were evaluated performing aerobic exercise sessions on an indoor bicycle at a moderate intensity (40-59% of heart rate reserve - HRR) and at a vigorous intensity (60-89% of HRR). Venous blood was collected for the analysis of lymphocyte proliferation before (baseline) and after each session. Concanavalin A (ConA) was utilized as stimulator and Alamar Blue® assay as measurement. The results were obtained by means of fluorimetric analysis after 24, 48 and 72 hours of cell culture after the exercise sessions. Statistical analysis comprised of repeated comparisons between the different sessions and the baseline by two-way ANOVA, considering p < 0.05. The vigorous exercise session reported a significant decrease in lymphocyte proliferative response of 21.96% (p = 0.011) in 24h, 37.46% (p = 0.001) in 48h and 27.61% (p = 0.005) in 72h, compared to the baseline. The moderate intensity exercise session reported a significant increase of 42.17% (p = 0.001) in 24h, 36.89% (p = 0.011) in 48h and 30.84% (p = 0.001) in 72h, compared to the baseline. There was a significant difference in delta variation between the two intensities (p < 0.005). Acute aerobic physical exercise at moderate and vigorous intensities caused a decrease and increase, respectively, in the lymphocyte proliferation of young adults.