Resistance exercise decreases beta-endorphin immunoreactivity.

Abstract

Previous research investigating the response of plasma P-endorphins to resistance exercise has resulted in equivocal findings. To examine further the effects of resistance exercise on 3-EP immunoreactivity, 10 male and 10 female college-age students participated in a series of controlled isotonic resistance exercises. The session consisted of three sets of eight repetitions at 80% of one repetition maximum (1-RM) for each of the following exercises: (1) bench press; (2) lateral pull-downs; (3) seated arm curls; and (4) military press. Blood plasma was sampled both before and after the lifting routine and P-endorphin levels were determined by radioimmunoassay. A Students t test for paired samples indicated that mean(s.e.) plasma P-endorphin levels after exercise (10.5(1.3) pg R-EP ml-') were significantly decreased as compared with pre-exercise (control) levels (16.5(1.2), P < 0.05). While the mechanism(s) contributing to the decrease in immunoreactivity is unclear, it may be the result of the synergistic effect of R-EP clearance during rest intervals and changes in psychological states between sampling.Keywords: Resistance exercise, P-endorphins Endurance exercise has been consistently shown to increase serum levels of 13-endorphinl-4. Limited research examining the effects of resistance exercise, however, has resulted in equivocal findings. Elliot Generalizations from the studies noted above are further complicated by differences in methodology such as lifting protocol and the duration of recovery intervals. The purpose of the present study was to examine further the effects of a controlled protocol of resistance (weightlifting) on plasma 13-endorphin immunoreactivity. MethodTen men recreational weightlifters (mean(s.e.) age 20.7(0.56) years; mean(s.e.) weight 79.9(2.2) kg; mean(s.e.) height 182.3(2.5) cm) and ten women basketball players (mean(s.e.) age 19.4(0.41) years; mean(s.e.) weight 68.6(1.7) kg; mean(s.e.) height 176.2(2.0) cm) volunteered to participate in the study. Each subject signed an informed consent document approved by the Human Investigation Committee of the University of Richmond. The participants were briefed on sampling and testing procedures after which blood was sampled from the group by venipuncture, placed on ice, then plasma was separated by centrifugation at 1500g for 10 min in a refrigerated centrifuge. The plasma was then stored in 1-ml aliquots at -70'C. Immediately after the first venipuncture, each subject began participation in a series of isotonic exercises using Nautilus (Lake Helen, Florida) resistance machines. This equipment was used (as opposed to 'free' weights) in order to standardize muscle movements and to control the duration of recovery intervals between exercises. The exercise session consisted of three sets of eight repetitions at 80% of one repetition maximum (1-RM) (or until muscular failure occurred) for each of the following exercises: (1) bench press; (2) lateral pull-downs; (3) seated arm curls; and (4) military press. One repetition maximum (1-RM) for eac...

β-Endorphin Immunoreactive Material and Authentic β-Endorphin in the Plasma of Males Undergoing Anaerobic Exercise on a Rowing Ergometer

“…More detailed investigations revealed that an anaerobic state, which was reached at a threshold of about 90 % of maximum oxygen consumption and was documented by a blood lactate level of more than 4 mmol/l arterialized blood, leads to a considerable increase of β-endorphin levels in human plasma under exercise [24,26]. Compatible with these findings was the fact that non-exhaustive performance such as heavy resistance exercise, although requiring high muscular activity for short time periods, did not lead to an increase of β-endorphin levels at all [20], even decreased them [21], or only allowed an increase under approximately exhaustive conditions [14]. On the other hand, one would have expected an enhancement of exhaustive exercise-induced β-endorphin release under additional hypoxia which, however, was not observed [5,13].…”

Do post‐concussion‐like symptom responses change following exercise or sports participation in a non‐concussed cohort?

“…However, the endorphin hypothesis has been mainly supported only in participants who engage in cardiovascular exercise 28,29 compared to resistance training. 30 In this present study, a greater number of females (n = 37) participated in cardiovascular only exercise compared to males (n = 6). Meanwhile, more males (n = 60) participated in resistance (weight training) only exercise compared to women (n = 7).…”

Níveis de beta-endorfina em resposta ao exercício e no sobretreinamento

“…(61) reportaram que não havia alterações significativas nos níveis de -end 1-31 em seis homens treinados, após a execução de três séries de oito repetições, a 80% da repetição máxima (1 RM). Em contraste, esses mesmos autores depois verificaram que os níveis de -end 1-31 diminuíam significativamente após a realização de um protocolo similar de exercício de força aplicado em estudantes (63). Outro estudo, em que sete homens treinados executaram um protocolo de três séries de 10 RM com quatro exercícios diferentes, demonstrou que um baixo volume de exercício de força não aumenta significativamente os níveis de -end (62).…”