The acute effect of maximal exercise on plasma beta-endorphin levels in fibromyalgia patients

BACKGROUND: This study aimed to investigate the effect of strenuous exercise on β-endorphine (β-END) level in fibromyalgia (FM) patients compared to healthy subjects. METHODS: We enrolled 30 FM patients and 15 healthy individuals. All study participants underwent a treadmill exercise test using modified Bruce protocol (M.Bruce). The goal of the test was achieving at least 70% of the predicted maximal heart rate (HRMax). The serum levels of β-END were measured before and after the exercise program. Measurements were done while heart rate was at least 70% of its predicted maximum. CONCLUSIONS: We found that FM patients had lower levels of β-END in both basal and post-exercise status. Exercise increased serum the β-END level in both groups but the average increase in β-END in FM patients was significantly lower than in the control group.