Carbohydrate supplementation and psychophysiological responses during moderate exercise in hypoxia.

BACKGROUND: Rating of Perceived Exertion (RPE) is a subjective scale to monitor overload and fatigue during exercise. Hypoxia may worsen the perception of fatigue, compromising the self-reported perception of effort and increasing RPE. The objective was to evaluate the effects of carbohydrate (CHO) supplementation on RPE during exercise in hypoxia simulating 4200 m. METHODS: Eight male physically active volunteers performed two exercises at 50% VO2peak and 1% slope: exercise in hypoxia + placebo or exercise in hypoxia + CHO (6% maltodextrin) with supplementation at 20, 40, and 60 min during exercise. Oxygen Saturation (SaO2%) was assessed at baseline and after exercise, while RPE and HR were measured each 10 min during the trial. RESULTS: SaO2% decreased after exercise in both conditions of hypoxia compared to rest. The RPE did not differ between groups. However, the RPE increased in hypoxia after 20 min of exercise in relation to 10 min. The Area Under the Curve (AUC) of RPE was lower in hypoxia + CHO compared to hypoxia. The AUC of the HR/RPE ratio in the hypoxia + CHO group was higher in relation to hypoxia. CONCLUSIONS: Our results indicate that CHO supplementation does not change RPE induced by 60 min of exercise at 50% VO2peak in hypoxia equivalent to 4200 m at the different times analyzed. However, in hypoxia + CHO the (AUC)-60 min of total RPE decreased during exercise, while the heart rate/RPE ratio improved, indicating lower RPE in the hypoxic environment.

Resistance exercise modulates lipid plasma profile and cytokine content in the adipose tissue of tumour-bearing rats.

Cancer cachexia is a multifactorial syndrome characterised by progressive weight loss, frequently accompanied by anorexia, sarcopenia, and chronic systemic inflammation. The white adipose tissue is markedly affected by cachexia and contributes to this syndrome throught the secretion of pro-inflammatory factors which reach the adjacent tissues and the circulation. A nonpharmacologic intervention that may attenuate cancer cachexia is chronic physical activity, but the effect of resistance training upon adipose tissue inflammation in cachexia has never been examined. For that purpose we designed a protocol in which animals were randomly assigned to a control group (CT, n=7), a Tumour bearing group (TB, n=7), a Resistance Trained group (RT, n=7) and a Resistance Trained tumour bearing group (RTTB, n=7). Trained rats climbed a vertical ladder with an extra load attached to the tail, representing 75-90% of total body mass, 3 times per week, for 8 weeks. In the 6 th week of resistance training, tumour cells (3 × 10(7) Walker 256 carcinosarcoma) were inoculated in the tumour groups. Body, adipose tissue, muscle and tumour mass was determined, as well a blood biochemical parameters, and the hormone and cytokine profile assessed. The glycogen content of the liver and muscle was measured. IL-10, IL-6 and TNF-α protein expression was evaluated in the mesenteric adipose tissue (MEAT) examined. Resistance training increased by 9% body weight gain in RTTB (final weight 310.8 ± 9.8 g), when compared with TB (final weight 288.3 ± 4.9 g). LDL-c levels were decreased in RTTB (0.28 ± 0.9 mmol/L) by 43% when compared with TB (0.57 ± 0.1 mmol/L). HDL-c levels were increased in RTTB (1.31 ± 0.12 mmol/L) by 15% in regard to CT (1.13 ± 0.7 mmol/L) and 22% as compared with TB (1.07 ± 0.07 mmol/L). RTTB testosterone levels (577 ± 131 ng/mL) were 55% higher when compared with CT (254 ± 41.3 ng/mL) and 63% higher when compared with TB (221 ± 23.1 ng/mL). Adiponectin levels were augmented in RT (23 µg/mL) by 43% when compared with TB (11 µg/mL). Protein expression of IL-6 was increased 38% in TB MEAT (5.95 pg/µg), as compared with CT (3.64 pg/µg) and 50% compared with RTTB (2.91 pg/µg). Similar results with respect to TNF-α TB (7.18 pg/µg) were observed: 39% and 46%, higher protein expression in comparison with CT (4.63 pg/µg) and RTTB (3.8 pg/µg), respectively. IL-10 protein expression was found to be increased in TB (4.4 pg/µg) and RTTB (3.2 pg/µg) 50% and 47%, respectively, in comparison with CT (1.2 pu/µg). The IL-10/TNF-α ratio was higher in RTTB in relation to all others experimental groups. The results show a robust effect of resistance exercise training in preventing important symptoms of cancer cachexia, thus strongly suggesting it may appear as an alternative to endurance exercise as a non-pharmacological therapy in the management of this syndrome.

Linear and daily undulating resistance training periodizations have differential beneficial effects in young sedentary women.

The aim of this randomized controlled study was to verify the impact of a 12-weeks muscular endurance (ME) training of high repetitions (i. e., 15-30) with 2 different periodization models on body composition, maximal strength, muscular endurance and cardiorespiratory fitness. Twenty eight sedentary women aged 20-35 years were randomly assigned to: control (CON) (n=8), linear periodization (LP) (n=10) and daily undulating periodization (DUP) (n=10). LP and DUP models significantly improved body composition, maximal strength and ME. However, no significant changes were detected for cardiorespiratory fitness. LP showed a higher body fat loss (- 12.73%) compared to DUP (- 9.93%) (p=0.049), and systematically higher effect sizes (ES) when compared with DUP for maximal strength and cardiorespiratory fitness parameters (e. g. ES=0.53 for ventilatory threshold). In contrast, DUP exhibited a significantly (p=0.002) greater ME gain (129.43%) compared to LP (70.72%) in bench press, and greater ES in all exercises. It may be suggested that LP performed with a high number of repetitions may be considered an appropriate periodization model for untrained young women that would likely lead to the improvement of body composition and maximum strength performance, whereas DUP is more effective for the development of ME.

Lymphocyte and cytokines after short periods of exercise.

The purpose of this study was to verify the effects of short periods of exercise of different intensity on lymphocyte function and cytokines. Thirty Wistar rats, 2 months old, were used. They were divided into five groups of six rats: a sedentary control group; a group exercised for 5 minutes at low intensity (5 L); a group exercised for 15 minutes at low intensity (15 L); and groups exercised at moderate intensity (additional load of 5 % of body weight) for 5 minutes (5 M) or for 15 minutes (15 M). The parameters measured were: total leukocytes, neutrophils, lymphocytes, monocytes, lymphocytes from lymph nodes, serum cytokines (IL-2, IL-6 and TNF-alpha), lymphocyte mitochondrial transmembrane potential, viability and DNA fragmentation. ANOVA two way followed by Tukey's post hoc test (p

Efeitos agudos do exercício de curta duração sobre a capacidade fagocitária de macrófagos peritoneais em ratos sedentários / Acute effects of short-duration exercise on the phagocytic capacity of peritoneal macrophages in sedentary rats

OBJETIVO: Analisar os efeitos agudos do exercício de curta duração em diferentes durações e intensidades sobre leucócitos totais, número e capacidade fagocitária de macrófagos peritoneais. MÉTODO: Foram utilizados ratos Wistar (n= 30, n= 6 por grupo), divididos em 5 grupos: controle sedentário (C); exercitados 5 minutos na intensidade leve ou moderada (5L e 5M, respectivamente); exercitados 15 minutos na intensidade leve ou moderada (15L e 15M, respectivamente). Na intensidade leve, o exercício foi realizado sem cargas; na moderada, foi utilizada carga adicional de 5 por cento do peso corporal dos animais em suas regiões dorsais. A contagem total de leucócitos e monócitos foi realizada no microscópio, cuja leitura foi procedida no aparelho LEUCOTRON TP. A porcentagem da fagocitose foi determinada por contagem em câmara de Neubauer através do número de células que fagocitaram três ou mais partículas de zymosan. Foram utilizados os testes ANOVA two way e Tukey com p < 0,05. RESULTADOS: Foi observado aumento nos leucócitos totais nos grupos exercitados (de 4,12 ± 0,17 x 10(6) para 8,69 ± 1,06 x 10(6) no grupo 5L, 9,5 ± 0,91 x 10(6) no grupo 15L, 12,56 ± 0,9 x 10(6) no grupo 5M e para 11,61 ± 0,6 x 10(6) no grupo 15M); aumento do número de macrófagos peritoneais após 15 minutos de exercício moderado (de 14,07 ± 0,57 x 10(6) para 20,9 ± 1,28 x 10(6)) e da capacidade fagocitária após 5 e 15 minutos de exercício leve de 74,8 ± 0,73 por cento para 79,8 ± 0,8 por cento e 83 por cento ± 0,44 por cento, respectivamente (p < 0,05). CONCLUSÕES: O exercício de curta duração promove aumento na capacidade fagocitária, fato esse de relevância para a reabilitação e esporte.

OBJECTIVE: To analyze the acute effects of short-duration exercise of different lengths and intensities on total leukocytes, peritoneal macrophage count and on the phagocytic capacity of peritoneal macrophages. METHOD: Five groups of Wistar rats were used (n= 30, n= 6 per group): one sedentary control group (C); two groups exercised for 5 minutes at low or moderate intensity (5L and 5M, respectively); and two groups exercised for 15 minutes at low or moderate intensity (15L and 15M, respectively). Low-intensity exercise was done without any load, while moderate-intensity was done with an additional load of 5 percent of the animal's body weight, attached to its back. The total leukocyte and monocyte counts were obtained under a microscope, and the readings were made with the Leucotron TP apparatus. The percentage phagocytosis was determined by counting in a Neubauer chamber, from the number of cells that phagocytized three or more particles of zymosan. Two-way ANOVA and Tukey tests were used, with p < 0.05. RESULTS: There was an increase in total leukocytes in the exercised groups (from 4.12 ± 0.17 x 10(6) to 8.69 ± 1.06 x 10(6) for 5L, 9.5 ± 0.91 x 10(6) for 15L, 12.56 ± 0.9 x 10(6) for 5M and 11.61 ± 0.6 x 10(6) for 15M), an increase in peritoneal macrophage count after 15 minutes of moderate exercise (from 14.07 ± 0.57 x 10(6) to 20.9 ± 1.28 x 10(6)) and an increase in phagocytic capacity after 5 and 15 minutes of light exercise (from 74.8 ± 0.73 percent to 79.8 ± 0.8 percent and 83 percent ± 0.44 percent, respectively) (p < 0.05). CONCLUSION: Short-duration exercise promotes increased phagocytic capacity. This is of importance for rehabilitation and sports.