The Effects of Exercise on the Levels of Beta-Endorphin in Blood

Athanasios Z. Jamurtas1, & Ioannis G. Fatouros2

1Department of Physical Education and Sports Sciences, University of Thessaly, Trikala, Hellas

2Department of Physical Education and Sports Sciences, Democritus University of Thrace, Komotini, Hellas

Beta endorphin (β-ΕΝ) is a 31-amino acid neuropeptide that is synthesized in the anterior lobe of hypophysis classified as an endogenous opioid. Opioids are defined as endogenous peptides whose properties are to some degree opium- or morphine-like. β-EN is secreted as part of a larger precursor molecule (pro-opiomelanocortin). β-ΕΝ release into circulation depends upon the intensity of exercise and it seems that there is a certain percentage of intensity (greater than 60% VO2max) and duration (> 5 minutes) that needs to be exceeded before its levels in the blood appear elevated. The response of β-ΕΝ in trained individuals, and in particular weight trained ones, is not clear yet. A few studies that examined the response of β-ΕΝ in cardiac patients seem to indicate that β-ΕΝ might be altered in individuals with health problems. Further research is needed to elucidate the role β-EN and opioids play during exercise.

Key words: opioids, training, weight training, health