This column contains a review of clinical trials conducted in exercise physiology laboratories by researchers at the Institute of Nutrition and Food Hygiene, Beijing, China, and University of North Texas Health Science Center, Fort Worth, Texas. The trials were sponsored by Pacific Health Laboratories, Inc., based in Woodbridge, NJ, the manufacturer of Endurox.

This is a summary of the research conducted on ciwujia, a natural root grown in the northeast section of China. Ciwujia has been used in traditional Chinese medicine to treat fatigue and bolster the immune system. The root has intrigued researchers because of anecdotal reports about its use by mountain climbers, who claimed ciwujia has improved work performance at high altitudes and low oxygen conditions. Ciwujia is marketed by Pacific Health Laboratories under the trademark Endurox. Following is a summary of two clinical trials to determine if Endurox could improve exercise performance:

Trial 1: In the first trial, 8 healthy male adults underwent an aerobic and anaerobic assessment using a stationary bicycle ergometer. Participants were asked to increase their energy expenditures measured in watts. Power was increased from 60 to 210 watts at 30-watt intervals. Each interval lasted three minutes. Subjects underwent minute by minute heart rate monitoring. Energy expenditure, oxygen intake, carbon dioxide expiration, and lactic acid were measured at the end of each interval. To assess anaerobic power, subjects started at a low resistance that increased to a specified load in three to five seconds. Subjects continued at their maximum strength for 30 seconds, at which time the maximum anaerobic power was recorded.

Following the initial assessment, each subject was administered 800 mg of Endurox daily for two weeks. They returned to the exercise physiology laboratory for a repeat of the aerobic and anaerobic assessments. After the administration of Endurox, there was a decrease in lactic acid levels, which became more pronounced at higher energy loads. At 150 to 180 watts, the decrease in lactic acid levels, when compared to the control group, ranged from 31 percent to 33 percent.

During exercise, carbohydrate and fat represent the primary sources of energy. A decline in the respiratory quotient (RQ) indicates that relatively less energy is produced by carbohydrate metabolism and more from fat metabolism. Following administration of Endurox, there was a significant drop in the RQ at various energy loads, which translated into a mean increase in fat utilization of 43.2 percent over controls. By shifting the energy source from carbohydrates to fat during exercise, Endurox increased fat metabolism and delayed the buildup of lactic acid.

Fifteen minutes following cessation of exercise, the mean heart rate in the Endurox group was 113 percent of the pre-exercise value versus 135 percent in the control group. The anaerobic threshold was computed by plotting lactic acid levels versus power load for each group. The Endurox group demonstrated a 12.4 percent increase in the anaerobic threshold over the control group.

Trial 2: To determine the effect on exercise with longer duration, 10 males ranging 18 to 23 underwent aerobic measurements using a power bike. Subjects pedaled under a light workload of 100 watts at a rotational speed of 60 rpms for 60 minutes. Heart rate, oxygen, CO2 and RQ were measured every four minutes. After the test was completed, measurements continued for 15 minutes. The subjects were then administered 800 mg of Endurox daily for 10 days and returned to the laboratory for a second assessment. There was a mean drop in RQ in the subjects administered Endurox of 0.09, which translates into a 30 percent increase in fat metabolism. There was also a statistically significant decrease in heart rate. The mean before-treatment value was 147, compared to 137 after administration of Endurox. Furthermore, oxygen intake per heartbeat increased 4.62 percent. During recovery, oxygen intake per heartbeat in the Endurox group increased 13 percent over the control group.

Conclusion: Endurox appears to be a safe and useful agent for improving exercise performance. The studies indicate that Endurox produces a carbohydrate-sparing action during both low- and high-intensity exercise. As a result of this effect, Endurox delays the lactic acid buildup associated with muscle soreness and fatigue and increases fat metabolism by up to 43 percent. These studies also show that Endurox increases the anaerobic threshold, speeds recovery following exercise and increases oxygen intake per heartbeat during exercise and recovery.

Information from Nutrition Science News