Effect of electroacupuncture on physical performance of young men and responses to exercise

Chinese Medicine uses acupuncture points K-3 (Taixi), Li-3 (taichong), S-36 (Zusanli), Ren-4 (Guanyuan)and Ren-6 (Qihai) to enhance the individual's general energy, improving capacity to physical efforts, and the body threshold to fadigue. We studied the influence of these specific points on physical performance capacity (PPC) and physiological responses to excercise (PRE). Material - We assigned 27 healthy men at random to three groups: acupuncture (A), acupuncture sham (S) and control group (no acupuncture (N). Methods - Performance was determined through of a spiroergometric test was carried out at the beginning and at the end of five sucessive daily sessions, consisting of 20 minutes of electroacupuncture (EA) of the selected points. They performed a continuous incremental (25 watts/min) test until exhaunstion in bicycle ergometer (Cibex the Bike). Respiratory and metabolic variables were calculated every 20s during excercise by a computerized spiroergometric system (Vista CX). The heart was obtained by telemetry (Polar), The rate of perceived exertion (RPE) was measured by the Borg's revised scale. Results - The results before and after treatment were compared in these conditions: rest (R); moderate exercise (M); at the anaerobic threshold (AT); intense exercise (I); maximal exercise (MX) and recovery (RC). The subjects from group A didn't increase the maximal performance capacity neither the PPC at AT. Respiratory, cardiovascular responses and movement economy in M, AT, I and MX didn't improve in these group. We detected a positive effect of EA only in RPE during M. There was no differences between tests in groups S an N. Conclusion - These results suggest that the EA in studied conditions isn't effective to increase PPC or improve PRE.

Effects of caffeine on the rate of perceived exertion

The role of caffeine in improving performance in endurance exercises is controversial and its mechanism of action is not well understood. The purpose of the present study was to evaluate the effects of caffeine on the rate of perceived exertion (RPE) by exercising athletes. Six male non-smoking runners, aged 26.8 ñ 4.9 years (mean ñ SD), who had been in training continuously for at least two years before the experiment were studied. Mean maximum oxygen consumption (VO2max) was 61.21 ñ 5.36 ml kg**-1 min**-1. The subjects were asked to exercise on a bicycle ergometer for 3 min each at 300 and 600 kg m min**-1, after which the work load was elevated to 1200 kg m min**-1 and they exercised until exhaustion. In order to evaluate the effects of caffeine, the exercicse was performed twice following the ingestion of 200 ml decaffeinated coffee with and without caffeine (5 mg/kg body veight). Caffeine had no significant effect on exercise time, pulmonary ventilation, oxygen consumption, carbon dioxide extraction or exchange respiratory ratio, but the RPE was significantly lower (P<0.05) at the work load of 1200 kg m min**-1 after the ingestion of caffeine for both trials I and II. The present results suggest that metabolic acidosis and glycogen depletion were not the main causes of exhaustion

Breathing pattern during pharmacological activation and blockade of the intermediate area of the ventrolateral surface of the cat medulla

The present study analyzes the respiratory pattern of chloralose- (50-60 mg/kg,iv) anesthetized cats treated with Nembutal (NE) (30 mg/ml), glycine (GL) (200 mg/ml) or leptazol (LE) (200 mg/ml) topically applied to the intermediate area of the ventrolateral surface of the medulla oblongata in a volume of 20 micronl. Application of NE and GL produced a decrease in ventilation (-24%) and tidal volume (-25%) suggesting that the intermediate area facilitates respiratory drive and inhibits the inspiratory off-switch mechanism. These results are consistent with the view that intermediate area is necessary for the central chemosensitivity to CO2. The topical application of LE produced an increase in inspiration time (12.5%), expiration time (20.8%) and tidal volume (7%). The increased tidal volume caused by LE is compatible with it action as a GL antagonist

Effect of exercise training during pregnancy: maternal and fetal responses of the rat

Pregnancy duration, offspring number, body weight gain per day, as well as offspring body and heart weights were studied in pregnant Wistar rats subjected to exercise training at relative work loads of 60, 70, 80 or 90% of maximum oxygen consumption (VO2max) (N = 6 for each group). Pregnancy duration, offspring number and heart weight of the rats subjected to exercise during pregnancy were not different from the control group not subjected to exercise training. Body weight gain per day of pregnant rats subjected to exercise was 4.64 + or - 0.21, 4.79 + or - 0.12 g, respectively, for work loads of 70,80 or 90% of VO2max. This decrease of body weight gain per day was ignificantly different (P<0.05) from the control group (5.69 + or - 0.22 g). The offspring body weight decreased in the rats submitted to work loads of 70,80 and 90% of VO2max(5.3-0 + or - 0.02 and 5.24 + or - 0.01g, respectively) by comparison to the control group value (5.73 + or - 0.07 g). These results suggest that only intense exercise could impair body weight gain in pregnant rats and their offspring