The purpose of this study was to examine blood pressure (BP), heart rate (HR), and cardiac vagal reactivation (VR) after an aerobic training session (ATS), a strength training session (STS), and a combined aerobic and strength training session (ASTS) in normotensive men. Eleven healthy men (age 26.8 ± 2.9 years, body mass index 24.3 ± 1.6 kg·m) with at least 6 months of strength and aerobic training experience performed an STS, an ATS, and an ASTS in a counterbalanced crossover design. Blood pressure and HR were measured at rest and at 15-minute intervals post-training for 1 hour. Vagal reactivation was measured during the first minute immediately post-exercise. After STS and ASTS, systolic BP (SBP) and mean arterial BP (MAP) remained significantly lower than at rest at all time intervals (p < 0.05). After ATS, SBP was significantly lower than at rest at 30 minutes and beyond (p < 0.01); however, no significant differences were observed for MAP. Post-training HR remained high after STS and ASTS at all intervals (p < 0.01). However, after ATS, the HR remained high only at the 15-minute post-exercise interval (p < 0.01). Vagal reactivation was significantly less pronounced after the first 30 seconds post-exercise (p < 0.01) in ASTS (531.3 ± 329.6 seconds) than in ATS (220.7 ± 88.5 seconds) and in STS (317.6 ± 158.5 seconds). The delta of the HR decrease at 60 seconds post-exercise was greater (p < 0.00) in ATS (33.4 ± 12.7 b·min) than in STS (14.1 ± 7.2 b·min) and in ASTS (11.4 ± 7.1 b·min). In conclusion, post-exercise BP reduction was independent of the type of exercise; however, HR remained significantly greater after combination of strength and aerobic exercise, implying a reduction in cardiac VR after this type of training. Therefore, strength and conditioning professionals may prescribe aerobic, strength, or a combination of aerobic and strength exercise to assist individuals concerned with BP control, thus allowing for variety in training while similarly impacting post-exercise SBP regardless of desired exercise modality.

We have studied the intrinsic modifications on myocardial automatism, conduction, and refractoriness produced by chronic exercise. Experiments were performed on isolated rabbit hearts. Trained animals were submitted to exercise on a treadmill. The parameters investigated were 1) R-R interval, noncorrected and corrected sinus node recovery time (SNRT) as automatism index; 2) sinoatrial conduction time; 3) Wenckebach cycle length (WCL) and retrograde WCL, as atrioventricular (A-V) and ventriculoatrial conduction index; and 4) effective and functional refractory periods of left ventricle, A-V node, and ventriculoatrial retrograde conduction system. Measurements were also performed on coronary flow, weight of the hearts, and thiobarbituric acid reagent substances and glutathione in myocardium, quadriceps femoris muscle, liver, and kidney, to analyze whether these substances related to oxidative stress were modified by training. The following parameters were larger (P < 0.05) in trained vs. untrained animals: R-R interval (365 +/- 49 vs. 286 +/- 60 ms), WCL (177 +/- 20 vs. 146 +/- 32 ms), and functional refractory period of the left ventricle (172 +/- 27 vs. 141 +/- 5 ms). Corrected SNRT was not different between groups despite the larger noncorrected SNRT obtained in trained animals. Thus training depresses sinus chronotropism, A-V nodal conduction, and increases ventricular refractoriness by intrinsic mechanisms, which do not involve changes in myocardial mass and/or coronary flow.

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Caffeine can affect muscle cell physiology and the inflammatory response during exercise. The purpose of this study was to analyse muscle damage markers and inflammatory cell infiltration into the soleus muscle of sedentary and exercised animals submitted to chronic caffeine intake. Thirty-two male Wistar rats were divided into the following four groups (n = 8 per group): sedentary control (SCO); sedentary + caffeine (SCAF); trained control (TCO); and trained + caffeine (TCAF). The animals were housed in individual cages and received tap water or caffeine (1 mg ml −1 ); they were maintained at rest or submitted to swimming for up to 40 min day −1 with a 4% load, five times per week for 30 days. Blood samples were collected for analysis of serum lactate, creatine kinase and calcium. The right soleus muscle and the epididymal fat depot were weighed, and the muscle was submitted to histological analysis. Training and caffeine did not change body or muscle weight, food and liquid intake or serum calcium levels among groups. Decreased fat tissue (P < 0.05) was observed in the SCAF (4.05 ± 1.03 g), TCO (4.14 ± 0.78 g) and TCAF groups (4.02 ± 1.02 g) compared with the SCO group (5.31 ± 1.06 g). Serum creatine kinase activity was significantly reduced in the SCAF (787.3 ± 230.3 U l −1 ), TCO (775.3 ± 232.3 U l −1 ) and TCAF groups (379.5 ± 110.5 U l −1 ) compared with the SCO group (1610.2 ± 276.5 U l −1 ). Few damaged muscle fibres (P < 0.05) were found in SCAF (16.7 ± 12.8%) and TCAF groups (17.3 ± 11.7%) compared with the SCO group (53.6 ± 13.9%). The SCAF group presented fewer fields with inflammatory cells (7.6 ± 8.7 fields) compared with the SCO group (123 ± 146 fields). The results suggest that the chronic intake of caffeine, as well as chronic low-intensity exercise, decreased muscle damage and inflammatory infiltration into skeletal muscle.

ABSTRACT.To investigate the effect of chronic moderate exercise on male reproductive tract of Wistar rats submitted to a single dose of cyclophosphamide (CP). Animals were submitted to swimming exercise during 21 days or maintained at sedentary state. Trained (TCP) and sedentary (SCP) groups received a single dose of CP (200 mg kg -1 , i.p.). Trained (TCo) and sedentary (SCo) control animals received sterile PBS. Animals were killed after one week and testis, epidydimis and seminal vesicle contend were weighted. Testis were embebbed in parafim and stained with hemotaxilin and eosin. Fifty seminiferous tubules of each animal were analyzed by Johnsen score. Mean Sertoli cells counts per tubule and Leydig cells counts per area were evaluated. CP treatment impairs body weight gain in trained and sedentary animals. Liver and seminal vesicle contend were reduced only in SCo group. SCP animals presented decreased Johnsen scores, indicating a slight toxicity over germinative cells, whereas trained (TCo and TCP) animals presented increased Johnsen scores. Training increased Sertoli cell counts and prevented their loss in TCP group. Leydig cells counts were increased in trained animals, but decreased in CP treated ones (TCP). We conclude that exercise have some protective effect on male reproductive tract submitted to a single dose of CP. , ip). Os animais treinados (TCO) e sedentários (SCO) receberam PBS estéril. Os animais foram sacrificados após uma semana e os testículos, epidídimo e conteúdo da vesícula seminal foram pesados. As amostras foram embebidas em parafina e coradas com hematoxilina e eosina. Cinquenta túbulos seminíferos de cada animal foram analisados pelo escore Johnsen. A contagem média das células de Sertoli por túbulo e contagem das células de Leydig por área foram avaliadas. O tratamento CP prejudicou o ganho de peso corporal em animais treinados e sedentários. O fígado e o conteúdo da vesícula seminal foram reduzidos apenas no grupo SCO. Os animais SCP apresentaram menores escores de Johnsen, indicando uma toxicidade moderada sobre as células germinativas, enquanto os animais treinados (TCO e TCP) apresentaram escores de Johnsen mais altos. O treinamento aumentou a contagem de células de Sertoli e impediu a sua perda no grupo TCP. A contagem das células de Leydig foram aumentadas em animais treinados, mas reduzidas nos animais tratados com CP (TCP). Concluiu-se que o exercício tem algum efeito protetor sobre trato reprodutivo masculino de animais submetidos a uma dose única de CP.Palavras-chave: ciclofosfamida, exercício, trato reprodutiva.

We have evaluated a new latex nephelometric test for the quantitation of myoglobin in human serum. The assay consists of incubating the diluted serum sample (20-fold) for 12 min at room temperature with latex particles covalently coated with anti-myoglobin antibodies and then quantifying the change of light-scatter produced. The assay is fully automated on the Behring nephelometer analyzer with a sampling rate of 150 samples/hour. There is no interference from bilirubin (up to 340 mumol/l), haemoglobin (up to 7,000 mg/l), or rheumatoid factor (up to 1,100 int. units/ml). Myoglobin standard curve extends from 20 to 380 micrograms/l. Assay detection limit lies around 6 micrograms/l. Coefficient of variation ranged from 2.7 to 7.6%. Correlation coefficient between latex immunoassay and an RIA method was 0.987, calculated from the assay of 37 samples. A statistically significant difference was found between the distribution for females and males. The serum level of myoglobin showed an age-dependent variation. Concentrations up to 60 micrograms/l are considered to be normal.

Conflict of interest: noneObjective: to analyze the morphological structure of cardiac, blood pressure (BP), heart rate (HR) and heart rate variability (HRV) of rats subjected to physical training with supplementation of caffeine. Methods: 60 rats were divided into 4 groups: control (CO), control with caffeine (CAF), trained control (TRE) and trained with caffeine (TCAF). All trained groups underwent 4 weeks of swimming, and all caffeine groups were supplemented by voluntary ingestion of caffeine diluted in drinking water. Results: there were no changes to BP and HR between groups. Regarding HRV, there was a decrease in LFnorm (low frequency) and LF/HF ratio (low and high frequency) in TCAF and CAF compared to group (p<0.02 and p<0.03, respectively). An increase occurred in CAF compared to the CO in the component LFnorm (p<0.05). The results also showed an increase in the relative weight of heart in the TRE (p<0.04) and TCAF (p<0.03) compared to CO. Conclusion: caffeine did not modify the hemodynamic responses. However, physical training resulted in a decrease in sympathetic response and an increase in relative heart weight.Uniterms: caffeine; exercise; arterial blood pressure; heart rate.