The effect of physical therapy on beta-endorphin levels

Beta-endorphin (beta E) is an important reliever of pain. Various stressors and certain modalities of physiotherapy are potent inducers of the release of endogenous beta E to the blood stream. Most forms of exercise also increase blood beta E level, especially when exercise intensity involves reaching the anaerobic threshold and is associated with the elevation of serum lactate level. Age, gender, and mental activity during exercise also may influence beta E levels. Publications on the potential stimulating effect of manual therapy and massage on beta E release are controversial. Sauna, mud bath, and thermal water increase beta E levels through conveying heat to the tissues. The majority of the techniques for electrical stimulation have a similar effect, which is exerted both centrally and-to a lesser extent-peripherally. However, the parameters of electrotherapy have not yet been standardised. The efficacy of analgesia and the improvement of general well-being do not necessarily correlate with beta E level. Although in addition to blood, increased brain and cerebrospinal fluid beta E levels are also associated with pain, the majority of studies have concerned blood beta E levels. In general, various modalities of physical therapy might influence endorphin levels in the serum or in the cerebrospinal fluid-this is usually manifested by elevation with potential mitigation of pain. However, a causal relationship between the elevation of blood, cerebrospinal fluid or brain beta E levels and the onset of the analgesic action cannot be demonstrated with certainty.