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Objective@#To investigate the possibility of heart rate as an optimum index for evaluating physical labor intensity.@*Methods@#From September to October, 2015, a total of 111 male young adults were selected as study subjects. A cycle ergometer was used for exercise at different intensities (20, 40, 60, 80, 100, 120, 140, 160, and 180 W) , and the exercise at each intensity lasted for 6 minutes. The subjects wore the K4b2 portable cardiopulmonary function testing instrument for the real-time monitoring of heart rate (HR) , pulmonary ventilation volume (Ve) , oxygen consumption (VO2) , and energy metabolic rate (E) . The origin software was used for correlation and regression analyses of HR, Ve, VO2, and E collected at different intensities to establish Ve-HR, VO2-HR, and E-HR regression equations.@*Results@#At different intensities, HR was positively correlated with Ve, VO2, and E (r=0.8985, 0.8733, and 0.8973, all P<0.01) . There was a significant difference in the R2 value of Ve-HR, VO2-HR, and E-HR regression equations (R2=0.8070, 0.7625, and 0.8049, all P <0.01) . The validation results showed that there was no significant difference between the calculated values and the measured ones (P>0.05) .@*Conclusion@#HR can replace Ve, VO2, and E and be used as an optimum index for evaluating physical labor intensity.
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AIM: To investigated the changes of hippocampus noradrenaline levels and its tyrosine hydroxyase (TH) , monoamine oxidase A (MAOA) expressions during chronic psycological stress procedure and physical exercise in rats. METHODS: Male Wistar rats (n =24) were randomly assigned to three conditions; (1) restraint stress (S) at 6 h/d for 3 weeks; (2) 24 h access to activity wheel running (E) for 4 weeks; (3) a sedentary control group (C). Levels of NE were assayed by high performance liquid chromatography with electrochemical detection. Protein expression of TH and MAOA were detected by Western blotting. RESULTS: Compared to C, weight loss and sucrose consumption rate decrease were induced in S, and NE was lower while TH and MAOA expressions increased significantly. In E group, NE was higher and TH, MAOA increased distinctly. CONCLUSION: It is suggested that hippocampus NE level may play an important role in the mechanism on the protection of physical exercise to chronic psycological stress, there is no close connection between NE change and TH, MAOA.Other mechanisms may exist.
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AIM: This study is to determine changes of hippocampal norepinephrine (NE) and serotonin (5 -HT) in long term physical exercise and chronic psychological stress, and to study the roles of the two monoamine transmitters in the effect of exercise counteracting stress - induced hippocampal damages in brain. METHODS : Levels of hippocampal NE and 5 - HT in rats undergoing 4 - week voluntary wheel running exercise (exercise group) or 3 - week restraint stress (stress group) or 4 - week exercise and 3 - week stress (exercise - stress group) were detected by high - performance liquid chromatography using electrochemical detection. RESULTS: It is showed that levels of hippocampal NEand 5 - HT increased significantly (P < 0. 01) in the exercised rats, and in the stressed rats, hippocampal 5 - HT levelssignificantly decreased(P < 0. 05). Additionally, the NE levels maintained significant high (P < 0. 01) in exercise -stressed rats compared to the pure stressed ones. On the other hand, no obvious difference was observed in hippocampal5 - HT levels between stress group and exercise - stress group, which were all significant lower (P < 0. 05) than that in exercise group. CONCLUSION: It is suggested that both the NE and 5 - HT may play important roles in mediating the exercise-induced positive effects and the 5 - HT may play an important role in stress - induced negative effects on the hippocampus. Moreover, NE may take more action in the exercise attenuating stress - induced hippocampal damages. The hippocampal NE may be more susceptible to exercise, and the hippocampal 5 - HT may be more susceptible to stress.`