Sobre la influencia del acullico de coca en la capacidad física / On the influence of coca acullico in the physical ability

El objetivo del presente estudio fue de evaluar el efecto del acullico de coca en la capacidad física de consumidores habituales de coca. La población del estudio fueron 22 hombres sanos del Altiplano Boliviano, 14 de los cuales no consumían coca más de 3 veces al año (grupo NC) y 8 acullicaban 3-4 veces por semana (grupo C). La metodología consistió en la medición del consumo máximo de oxígeno y parámetros relacionados así como variables bioquímicas en dos pruebas de esfuerzo en bicicleta ergométrica: La primera fue una prueba de esfuerzo controlado progresivo hasta el máximo y la segunda una prueba de esfuerzo submáximo prolongado a una carga de trabajo de 60-70% de la carga máxima alcanzada en la primera prueba. El grupo C hizo ambas pruebas después de haber acullicado coca durante una hora previa. Se obtuvieron varias muestras de sangre venosa de ambos grupos de sujetos para obtener valores sanguíneos de lactato, adrenalina, noradrenalina, glucosa, insulina y ácidos grasos libres. Los resultados de la prueba máxima evidenciaron un consumo máximo de oxígeno similar en ambos grupos. La única diferencia signifi cativa fue una mayor desaturación de oxígeno en el grupo C que en el grupo NC. Las diferencias entre C y NC se evidenciaron en la prueba submáxima de esfuerzo prolongado donde C mantuvo el consumo de oxígeno estable mientras que NC incremento este parámetro signifi cativamente. Además el grupo C tuvo niveles mayores de adrenalina, noradrenalina y de glucosa y de ácidos grasos circulantes así como niveles menores de insulina. Concluimos que los acullicadores no pueden realizar un trabajo más intenso que los no-acullicadores, pero que pueden tolerar mejor el esfuerzo prolongado como demuestra el consumo de oxígeno estable. El incremento del nivel de glucosa y de los ácidos grasos libres circulantes en C indica que la mejor tolerancia...

The aim of our study was to assess the effects of coca chewing on the exercise capacity of habitual coca chewers. The study population were 22 healthy men from the Bolivian Altiplano, 14 of which did not chew coca more than 3 times per year (group NC) and 8 used coca 3-4 times per week. The methodology consisted in measuring maximal oxygen uptake and related parameters as well as biochemical variables during 2 exercise tests on a bicycle ergometer. The fi rst test was of controlled progressive exercise up to maximal level, and the second consisted of prolonged submaximal exercise during one hour at 60-70% of the maximal level reached in the fi rst test. Group C did both tests after having chewed coca during one hour previously. Various venous blood samples were obtained from both groups for measuring blood levels of lactate, epinephrine, nor-epinephrine, glucose, insulin and free fatty acids. The results of the maximal exercise test showed similar values of maximal oxygen uptake in both groups. The only signifi cant difference was a greater oxygen desaturation in group C than in NC. The differences between C and NC became evident in the prolonged submaximal test, where C maintained the oxygen uptake whereas NC increased the oxygen consumption signifi cantly. Additionally, group C had higher levels of epinephrine, norepinephrine, glucose and free fatty acids and lower levels of insulin. We concluded that coca chewers are not able to do more intensive work than non-chewers, but that they tolerate effort better as shown by their stable oxygen uptake. The increase of glucose levels and circulating free fatty acids indicates that the better tolerance of prolonged effort in C might be due to a belated decrease of the glycogen stores.

Usefulness of the Oxygen Uptake Efficiency Slope in the Evaluation of Cardiorespiratory Fitness of the Stroke Patients

OBJECTIVE: To investigate the usefulness of the oxygen uptake efficiency slope (OUES) in the evaluation of cardiorespiratory fitness of the stroke patients. METHOD: 25 stroke patients who could walk independently were included in this syudy. The symptom-limited graded treadmill test was performed to assess cardiovascular fitness. During the test, minute ventilation (VE), oxygen consumption (VO2), carbon dioxide production (VCO2), respiratory exchange ratio (RER) and anaerobic threshold (AT) were measured through respiratory gas analysis. A linear relationship was established between the oxygen consumption and the logarithmic transformation of minute ventilation. From this linear relationship, we obtained a slope that represented the OUES. OUES values were obtained from data corresponding to 75% (OUES75), 90% (OUES90) and 100% (OUES100) of the exercise duration. RESULTS: The differences among OUES75, OUES90 and OUES100 groups were not statistically significant and these three groups were highly correlated to each other. Maximal oxygen consumption (VO2max) was positively correlated with OUES75 (r=0.723), OUES90 (r=0.762), OUES100 (r=0.809) and AT (r=0.696), respectively (p<0.01). CONCLUSION: OUES is considered to be the valuable submaximal index to evaluate the cardiorespiratory fitness of stroke patients who can not reach maximal exercise.

Validity analysis of for exercise tests in assessing aerobic capacity of young men

BACKGROUND: Assessment of aerobic capacity (VO2max) is one of the essential components in exercise prescription for health promotion and maintenance. This study was conducted to compare the validity of four exercise tests to assess aerobic capacity in young adult male subjects by comparing them to the values measured from maximal ergometer exercise test (criterion VO2max). METHODS: Twenty young healthy adult males (M+/-SD=21.1+/-1.5 years) volunteered as subjects. Criterion VO2max was calculated and printed out automatically by computerized analysis system of expired air samples collected during maximal ergometer exercise test. VO2max was estimated for each subject from heart rate at submaximal workloads on the cycle ergometer using the Astrand-Rhyming nomogram(A/R) and Fox protocol(FOX) and the computerized multiple extrapolation method (XTP). The score got from Havard step test(H/S) was used to compare the validity. The validity of the procedures was based on the evaluation of the predicted VO2max (from A/R, FOX, XTP, and H/S) versus the criterion VO2max via the calculation of constant error (CE=mean difference for predicted minus criterion VO2max), r value, standard error of the estimate[SEE=SD(1-r2)(1/2)], total error [TE=(sigma(predicted VO2max - criterion VO2max)(2)/n)(1/2)]. RESULTS: In relation to criterion VO2max, the XTP and A.R underpredicted (XTP: 40.8 ml/kg/min SD=4.1; A/R: 37.3 ml/kg/min SD=5.0) and the H/S and FOX overpredicted (H/S: 48.0 ml/kg/min SD=5.9: FOX 46.3 ml/kg/min SD=5.5). Dunnett post-hoc procedures revealed that there were significant (P<0.05) mean differences (CE) for VO2max from A/R versus criterion. The validity coefficients for VO2max derived from XTP, H/S, A/R, and FOX were 0.68, 0.53, 0.50, and 0.49, respectively. TE of the XTP, FOX, H/S and A/R, which accounts for the effects of both the CE and SEE, were 5.73, 6.13, 6.75, and 8.87, respectively. CONCLUSIONS: These results suggest that the XTP is recommended first for estimation VO2max in young adult males. It is also considered that further studies about female and other age groups are necessary.