Resistance training increases muscle strength in older adults, decreasing the effort necessary for executing physical tasks, and reducing cardiovascular load during exercise. This hypothesis has been confirmed during strength-based activities, but not during aerobic-based activities. This study determined whether different resistance training regimens, strength training (ST, constant movement velocity) or power training (PT, concentric phase performed as fast as possible) can blunt the increase in cardiovascular load during an aerobic stimulus. Older adults (63.9 ± 0.7 years) were randomly allocated to: control (N = 11), ST (N = 13, twice a week, 70-90% 1-RM) and PT (N = 15, twice a week, 30-50% 1-RM) groups. Before and after 16 weeks, oxygen uptake (VO 2 ), systolic blood pressure (SBP), heart rate (HR), and rate pressure product (RPP) were measured during a maximal treadmill test. Resting SBP and RPP were similarly reduced in all groups (combined data = -5.7 ± 1.2 and -5.0 ± 1.7%, respectively, P < 0.05). Maximal SBP, HR and RPP did not change. The increase in measured VO 2 , HR and RPP for the increment in estimated VO 2 (absolute load) decreased similarly in all groups (combined data = -9.1 ± 2.6, -14.1 ± 3.9, -14.2 ± 3.0%, respectively, P < 0.05), while the increments in the cardiovascular variables for the increase in measured VO 2 did not change. In elderly subjects, ST and PT did not blunt submaximal or maximal HR, SBP and RPP increases during the maximal exercise test, showing that they did not reduce cardiovascular stress during aerobic tasks.

1. Serotonin is a neurotransmitter that modulates several functions, such as food intake, energy expenditure, motor activity, mood and sleep. Acute exhaustive endurance exercise increases the synthesis, concentration and metabolism of serotonin in the brain. This phenomenon could be responsible for central fatigue after prolonged and exhaustive exercise. However, the effect of chronic exhaustive training on serotonin is not known. The present study was conducted to examine the effect of exhaustive endurance training on performance and serotonin concentrations in the hypothalamus of trained rats. 2. Rats were divided into three groups: sedentary rats (SED), moderately trained rats (MOD) and exhaustively trained rats (EXT), with an increase of 200% in the load carried during the final week of training. 3. Hypothalamic serotonin concentrations were similar between the SED and MOD groups, but were higher in the EXT group (P < 0.05). Performance was lower in the EXT group compared with the MOD group (P < 0.05). 4. Thus, the present study demonstrates that exhaustive training increases serotonin concentrations in the hypothalamus, together with decreased endurance performance after inadequate recovery time. However, the mechanism underlying these changes remains unknown.

Strenuous exercise promotes changes in salivary IgA and can be associated with a high incidence of upper respiratory tract Infections. However, moderate exercise enhances immune function. The effect of exercise on salivary IgA has been well studied, but its effect on other immunological parameters is poorly studied. Thus, this study determined the effect of moderate acute exercise on immunological salivary parameters, such as the levels of cytokines (TGF-β and IL-5), IgA, α-amylase and total protein, over 24 h. Ten male adult subjects exercised for 60 min at an intensity of 70% VO2 peak. Saliva samples were collected before ('basal') and 0, 12 and 24 h after an exercise session. The total salivary protein was lower after 12 and 24 h than immediately after exercise, whereas α-amylase increased at 12 and 24 h after exercise compared with basal levels. The IgA concentration was increased at 24 h after exercise relative to immediately after exercise, and there was no difference in the IL-5 while TGF-β concentration increased in recovery. In conclusion, 70% VO2 peak exercise does not induce changes immediately after exercise, but after 24 h, it produces an increase in salivary TGF-β without changing IL-5.

The purpose of this study was to evaluate the serum level of serotonin (5-HT) during rest and response to exercise in subjects with spinal cord injury (SCI) with di erent levels of physical activity. Twenty-®ve male subjects with traumatic paraplegia, the neurological levels being between T1 and T12, volunteered for the study. They were divided into two groups matched for age, weight and time since injury, according to the level of physical activity: 14 inactive and 11 subjects regularly involved in sports activity and considered active. They all performed a maximal spiroergometric test with an arm crank ergometer. Two samples of blood were collected for 5-HT determination, during rest (PRE) and immediately after exercise test (POST). Serum 5-HT concentration was measured by high performance liquid chromatography using electrochemical detection (HPLC-ED). The results showed that peak oxygen uptake (V . O 2peak ) was higher in the active group (27.08+2.60 vs 18.89+5.58 mL.kg 71 .min 71 , P50.001). There were no signi®cant di erences between the inactive and active groups for the 5-HT PRE (respectively 176.96 and 193.73 ng.mL 71 , P40.05) or POST values (275.44 vs 311.05 ng.mL 71 , P40.05). Both groups showed an increment in 5-HT after maximal exercise, but only in the active group it reached statistical signi®cance (Wilcoxon test, P50.02). Our results show that chronic paraplegic individuals have normal resting serum serotonin levels and normal response to exercise. The relationship between training status, mood elevation and 5-HT in SCI could not be established in the present study, and further investigation is needed to clarify this issue.

RESUMOO objetivo deste estudo foi analisar a validade da velocidade crítica (VC) para estimar o limiar anaeróbio (LAn), antes e após dois diferentes programas de treinamento em atletas de endurance. Dezessete corredores (33,4 ± 4,4 anos; 62,7 ± 4,3 kg; 166,1 ± 5,0 cm) divididos em 2 grupos (G95% -N = 9 ; G100% -N = 8) realizaram os seguintes testes: 1) Tiros máximos de 1500 e 5000 m para a determinação da VC; 2) Testes para a determinação do consumo máximo de oxigênio (VO 2 max) e sua respectiva velocidade (vVO 2 max), economia de corrida (EC), LAn e tempo de exaustão (Tlim) nas intensidades de 95 e 100% vVO 2 max. Os testes foram realizados antes e após 4 semanas de treinamento, o qual foi semelhante entre os grupos, exceto nos 2 dias de treinamento intervalado.