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Serum β-endorphin levels during a graded exercise test to exhaustion

GOLDFARB ALLAN H.; HATFIELD, BRADLEY D.; SFORZO, GARY A.; FLYNN, MICHAEL G.
Medicine & Science in Sports & Exercise: April 1987
ORIGINAL INVESTIGATIONS: PDF Only

ABSTRACT

GOLDFARB, A. H., B. D. HATFIELD, G. A. SFORZO, and M. G. FLYNN. Serum β-endorphin levels during a graded exercise test to exhaustion. Med. Sci. Sports Exerc, Vol. 19, No. 2, pp. 78–82, 1987. Nine untrained college age males completed a graded exercise protocol to maximal capacity on a bicycle ergometer to determine if there was a relationship between intensity of exercise and serum β-endorphin (β-EP) levels. Subjects fasted for 12 h and abstained from physical activity at least 24 h prior to testing. Subjects completed the Multiple Affect Adjective Check List prior to and following exercise to ascertain if psychological state would be associated with β-EP levels. The initial workload was 150 kilopond meters and was increased 150 kilopond meters every 3 min until JOURNAL/mespex/04.02/00005768-198704000-00002/ENTITY_OV0312/v/2017-07-20T222146Z/r/image-pngO2max or leg fatigue occurred. Expired gases were continuously analyzed, and a venous blood sample was drawn from an indwelling catheter during the final 30 s of each stage and 5-min post-exercise. β-EP levels were determined from serum using a radioimmunoassay technique and corrected for cross-reactivity with β-lipotropin using affinity chromatography. Resting β-EP levels were 25.3 ± 4.1 pg·ml-1 and did not demonstrate significant changes during any stage of exercise. A correlation analysis (r = 0.30) revealed no significant relationship between exercise intensity and β-EP levels. Following exercise, β-EP levels were significantly increased compared to resting values (38.8 ± 4.8 pg·ml-1). In addition, psychological state was unaffected by exercise despite significant increases in recovery β-EP levels. These data support previous studies reporting increases in β-EP levels following exercise, but do not indicate a relationship between intensity of exercise and β-EP levels during graded exercise or peripheral β-EP levels and psychological state.

©1987The American College of Sports Medicine