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

Abstract

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.