Järvekülg A, Viru A
Institute of Exercise Biology, University of Tartu, Estonia.
Int J Sports Med. 2002 Apr;23(3):155-7. doi: 10.1055/s-2002-23168.
The contribution of opioid receptors to the mood effects of aerobic gymnastics was tested by oral administration of naltrexone (25 or 50 mg) in 12 healthy women (aged 22 - 30 years). The opioid receptor blockade eliminated decreased anxiety, negative affect level and depressiveness as well as increased positive affect level, as found in a placebo trial after a 50 min session of aerobic gymnastics. 50 mg of naltrexone was more effective than 25 mg. Administration of 50 mg of naltrexone without exercise did not cause any significant changes in anxiety, positive and negative affect levels or depressiveness.
