Recent research demonstrates the dramatic effect exertion has on the body’s glutamine reserves. For example, athletes doing intensive anaerobic exercise showed a 45% drop in plasma glutamine compared to pre-exercise levels. When the same athletes continued aerobic exercise for 10 days, their plasma glutamine dropped by 50%. Some still had depressed glutamine levels even six days after recovery from the exercise3. This suggests that they need more glutamine than their diets provided and their liver could manufacture. Athletes who overstress their muscles (without adequate time for recovery and/or without glutamine replenishment) may be at increased risk of infection and often recover slowly from injuries.