RESUMO
The purpose of this study was to clarify the effects of amino acid supplementation on mental and physical stress during severe exercise. 20 male college students were assigned to amino acid treated group (group AA) and placebo treated group (group P), each containing 10 subjects, and performed 1600 m-run relay for 24 hours. Each subjects of AA group received 1 g of amino acid powder, containing 34% of branched-chain amino acid (BCAA), after each work bout. The score of rating of perceived exertion (RPE) and category rate of pain scale (CPS) for each work bout were recorded. Scoring of profile of mood states (POMS) was performed and blood samples were drawn at pre-, mid-, and post-session. Total running distance was similar in both groups. In group AA, compared with group P, (1) total score of RPE and CPS through 25 work bouts and plasma cortisol concentration (C) at post- was significantly lower, and (2) molar ratio of plasma free testosterone concentration (FTS) to C (FTS/C) at mid- was significantly greater. In group P alone, plasma BCAA concentration, FTS, FTS/C, and POMS score about ‘tension-anxiety’, ‘anger-hostility’ and ‘vigor’ decreased significantly over time. Our data suggest that BCAA administration during severe exercise may diminish mental or physical stress, inhibit FTS/C decrease and be effective in maintaining aggressive mentality.
RESUMO
This report deals with the response of heart rate, blood pressure and respiratory rate when the subjects of different ages and sexes worked on a bicycle ergometer. The subjects were 126 healthy persons of both sexes. They consisted of 8 groups : prepuberty male (N=15) and female (N=16), puberty male (N=20) and female (N=18), young adult male (N=15) and female (N=16), middle aged male (N=17) and female (N=9) . All subjects tried pedalling exercise with 3 kinds of loads, i.e., 5kgm/kg/min, 10kgm/kg/min and 12.5 kgm/kg/min for 6 minutes.<BR>Heart rate was calculated from chest lead ECG and respiratory rate was measured by the thermistor method continuously recorded before, during and after exercise. Blood pressure was measured by Riva Rocci sphygmomanometer before exercise, at the early stage of recovery and in 10 minutes after exercise.<BR>The results of this study are summarized as follows<BR>1) In both sexes the heart rate decreased with age in resting status and exponentially increased during moderate and heavier exercise. A linear relationship was found between the work load and the exercise heart rate.<BR>In males the heart rate during light exercise was high in the prepuberty and the puberty, low in the young adult and the middle aged. But the heart rate during heavy exercise in the middle aged was extremely high. The heart rate in females was higher than that in males when the same work load was given in both sexes. The rising phase of heart rate in prepuberty was the earliest of 4 age groups.<BR>2) The systolic blood pressure and the pulse pressure in resting status increased with age. As for the blood pressure during exercise, it was low in the youth and high in the middle aged. The blood pressure after exercise in the middle aged males was the highest of 4 groups. Generally in all females the systolic blood pressure and the pulse pressure increased with work load, but the former levelled off during heavy exercise.<BR>3) The respiratory rate during exercise increased rapidly, but when the exercise was stopped, the increased respiratory rate returned rapidly to the resting level. As for the respiratory rate, in both sexes it decreased with age from the prepuberty to the middle aged in resting status and during exercise. The sex difference of the respiratory rate during heavy exercise was large.<BR>4) In the youth the correlation coefficient between the heart rate and the blood pressure was high. Therefore, it was suggested that the heart rate was important in adaptation to exercise.