Ginseng supplementation does not change lactate threshold and physical performances in physically active Thai men.

BACKGROUND: Ginseng has been one of the most popular herbs said to improve human exercise performance. Unclear and anecdotal information is known about the effect of ginseng on lactate threshold and aerobic performance in humans. OBJECTIVE: The purpose of the present study was to investigate the effect of ginseng supplementation on lactate threshold in physically active young men. MATERIAL AND METHOD: Sixty men from the Naval Medical Corps, Royal Thai Navy, aged 17- 22 years old, were randomized into either the ginseng (n = 30) or placebo (n = 30) group. The ginseng group took 3 grams of 100% ginseng orally, while the placebo group took an equal amount of lactose powder each day, for 8 weeks. Blood lactic acid levels for determination of lactate threshold (LT) were measured during an incremental cycle ergometer work. LT exercise performance, and heart rate (HR) responses to exercise were determined at baseline and after 8 weeks of ginseng and placebo consumption. Substrate oxidation rates during steady state exercise were assessed upon study completion. Selected markers for liver and kidney functions, including serum aspartate aminotransferase, alanine aminotransferase, blood urea nitrogen, and creatinine were monitored for possible side effects of ginseng. RESULTS: L T before and after 8 weeks of supplementation in the ginseng group (164.5 +/- 32.8 and 170.9 +/- 26.4 watts), and in the placebo group (163.7 + 25.1 and 163.7 + 17.3 watts) were not different (p = 0.448). Both groups had a similar pattern of exercise heart rate (p = 0.918), total exercise time (p = 0.241), and peak power output (p = 0.411). After 8 weeks, the magnitude of difference between ginseng and placebo groups on oxidation rates of fat (3.82 +/- 10.0 cal. kg(-1). min(-1), p = 0.704) or carbohydrate (4.36 +/- 12.6 cal. kg(-1). min(-1), p = 0.731) was not statistically significant. There were no abnormal changes of markers of liver and renal functions after ginseng administration. CONCLUSION: Daily administration of 3 g of ginseng for an 8-week period did not improve LT nor did it affect physical performances. Therefore, ginseng supplementation did not exert an ergogenic property on aerobic fitness enhancement in well-fit individuals.

Effects of cardiac rehabilitation on fibrinolysis in patients with coronary artery disease.

The aim of the present study was to demonstrate the influence of exercise component of a cardiac rehabilitation program on fibrinolysis in coronary artery disease (CAD) patients. Cardiac rehabilitation program was claimed to have an important role for improving quality of life and reducing the incidence of recurrent disease. The program used in the present study included aerobic exercise for 8 weeks, 4 days per week, 30 minutes per day at light to moderate intensity. Thirty-three male patients with CAD were recruited in the present study. Subjects from Thammasat University Hospital and King Chulalongkorn Memorial Hospital, whose age ranging from 40 to 70 years, were random assigned into 2 groups: control and experimental groups. The results showed that no significant differences in tissue plasminogen activator levels (t-PA) (both antigen and activity), plasminogen activator inhibitor-1 levels (PAl-1) (both antigen and activity) were observed in control and experimental groups after exercise training for 8 weeks as compared to the baseline. However significant improvement of fibrinolysis via a decrease in PAI-1 activity level from 16.3 (3.7) to 14.8 (6.3) AU/ml (p < 0.024) and an increase in t-PA activity from 2.3 (0.8) to 2.7 (0.5) IU/ml and t-PA antigen from 7.5 (2.9) to 9.2 (2.7) ng/ml (p < 0.01) in experimental group were observed when compared between pre and post acute submaximum exercise (65% VO(2 peak)) at the end of the program. In addition the authors found a significant improvement in VO(2 peak) resting heart rate, and serum triglyceride level in experimental group after 8 weeks of exercise training. This study demonstrated that patients with CAD participating in 8 weeks exercise cardiac rehabilitation program at light--moderate intensity could improve physical fitness and physical health although there was no significant change of fibrinolysis. The CAD patients should be advised to enroll in this cardiac rehabilitation program since it did not have any harmful effect due to the fibrinolytic function but it also augmented the patients' physical health.

Low dose creatine supplementation enhances sprint phase of 400 meters swimming performance.

This study demonstrated the effect of low dose creatine supplement (10 g. per day) on the sprinting time in the last 50 meters of 400 meters swimming competition, as well as the effect on exertion. Nineteen swimmers in the experimental group received creatine monohydrate 5 g with orange solution 15 g, twice per day for 7 days and nineteen swimmers in the control group received the same quantity of orange solution. The results showed that the swimmers who received creatine supplement lessened the sprinting time in the last 50 meters of 400 meters swimming competition than the control group. (p<0.05). The results of Wingate test (anaerobic power, anaerobic capacity and fatigue index) compared between pre and post supplementation. There was significant difference at p<0.05 in the control group from training effect whereas there was significant difference at p<0.000 from training effect and creatine supplement in the experiment group. Therefore, the creatine supplement in amateur swimmers in the present study enhanced the physical performance up to the maximum capacity.

Changes of immune system in military recruits after the training program.

The aim of the exercise was to improve body health including the immune system function. However, several studies have observed the suppression of immune response in athletes who were trained with strenuous exercise. Recruits who have been in the recruitment-training program for 8 weeks might also have immune suppression. Twenty males, aged from 21 to 23 years in Chulachomklao Royal Military Academy infantry battalion volunteered to participate in this study. They were asked to wear a Polar Accurex Plus Telemetric heart rate monitor during the training period. Tuberculin skin test which is the screening method for cellular immune responses was significantly decreased at post-training compared to the pre-training (p<0.02). The levels of serum IgG and IgM at pre-training, 4th week, 8th week and one week post-training were significantly decreased at the initiation period, which were compared with pre-training and 4th week of training (p<0.01), and returned to normal at the 8th week of training and one week post-training. The level of circulating immune cells and number of CD markers (CD3, CD4, CD8, and CD56) were not significantly changed throughout the training period. This study demonstrated that subjects who underwent the recruit-training program were able to improve their health after the period of training i.e., in the adaptation period. The decrease in the initiation period could be compensated with proper diet and enough rest.