European heart journal
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European heart journal · Dec 1988
Comparative Study Clinical Trial Controlled Clinical TrialEffect of physical exercise on pain thresholds and plasma beta-endorphins in patients with silent and symptomatic myocardial ischaemia.
In a double-blind study, eight patients with symptomatic myocardial ischaemia and nine with asymptomatic myocardial ischaemia were compared during physical exercise under naloxone (6 mg i.v.) or placebo. Plasma beta-endorphin, cortisol and catecholamines were measured before exercise, during maximal exercise, and 10, 20 and 60 min after exercise. A tourniquet pain test (on the forearm, under control of transcutaneous PO2), and an electrical pain test (intracutaneous electrode placed in the finger with the electrical stimulus under computer control and two-interval forced-choice psychophysical technique) were performed before exercise as well as immediately after, and 60 min after exercise. ⋯ Electrical pain thresholds, though on average higher in asymptomatic patients (2.21 mA vs. 0.79 mA), were not affected by exercise or naloxone. Asymptomatic patients required more time to reach pain thresholds in the tourniquet pain test (P less than 0.02). After exercise, tourniquet pain thresholds were significantly lower (P less than 0.01) under naloxone compared with placebo.(ABSTRACT TRUNCATED AT 250 WORDS)