Effects of Low-Volume Resistive Exercise on Beta-Endorphin and Cortisol Concentrations

It has been recently suggested that high and sustained lactate levels may elicit increases in peripheral B-EN concentrations (16). We have observed elevated and sustained lactate concentrations in response to a low-volume resistive exercise protocol (14) that were similar to those from other exercise protocols that produced elevated beta-endorphin (B-EN) concentrations. Thus, the purpose of the study was to determine the effects of a low-volume (21,700 J) resistive exercise repetition maximum (RM) protocol using weight machines on peripheral lactate, B-EN and Cortisol concentrations. Subjects completed 3 sets of bench press, lat-pull, leg extension, and leg curl exercise at a 10-RM load. Blood samples were collected and rating of perceived exertion (RPE, 15-point Borg scale) was assessed before exercise (- 40 and - 10 min), after each exercise, and after the exercise session (+ 35 min); blood samples were collected at 7 additional post-exercise times. RPE increased significantly throughout the exercise. Lactate concentrations rose significantly to peak at 8.54 mM at LE. B-EN and Cortisol concentrations (- 10) of 4.63 ± 0.54 pmol · l^-1 and 12.09 ± 1.44 μg · dl^-1, respectively, were not significantly elevated over time. The data suggest that a low-volume resistive exercise protocol using weight machines elevates lactate concentrations without altering B-EN and Cortisol concentrations.

Key words

Pituitary-adrenal axis - weight training - lactate