Phenylethylamine, a possible link to the antidepressant eVects of exercise?

Objectives—To determine in this pilot study whether aerobic exercise aVects phenylacetic acid concentration in the urine. Methods—Twenty healthy men provided 24 hour urine samples on two consecutive days for the determination of phenylacetic acid levels. Before and during day 1, subjects refrained from physical activity; on day 2 subjects ran on a treadmill at 70% of their maximal heart rate reserve (MHRR) for 30 minutes. Results—The 24 hour mean urinary concentration of phenylacetic acid was increased by 77% after exercise. Conclusion—As phenylacetic acid concentration in urine reflects phenylethylamine level, which is known to have antidepressant eVects, phenylethylamine may be linked to the therapeutic eVects of physical exercise on depression. (Br J Sports Med 2001;35:342–343)