βeta-endorphin levels following acute physical exercise in young and middle-aged adults

A large and growing body of literature has explored the impact of physical exercise (PE) on human health, shedding light on its crucial role for brain health [1]. Recent research suggests βeta-endorphin (βE) as a promising candidate for mediating the exercise-induced stimulation of neurogenesis [2] Moreover, PE can elevate the levels of brain-derived neurotrophic factor (BDNF), further promoting the process of neurogenesis [3]. To date, few studies have analysed age-related differences in βE secretion following acute PE and no study has investigated its association with BDNF in humans. The purposes of this study were to examine the exercise-induced changes in βE release in two age groups of healthy adult males and to explore potential correlations between βE and BDNF. Thirty-four participants (22 young adults, YA: age, 24.6±3.5 yrs; BMI, 23.2±2.3 kg/m2; peak oxygen uptake (V̇O2peak), 49±9.8 ml/kg/min and 12 middle-aged adults, MA: age, 54.6±5.7 yrs; BMI, 23.4±2.2 kg/m2; V̇O2peak, 44.8±5.1 l/kg/min), underwent an incremental cycling test to exhaustion. Respiratory gases were measured breath-by-breath using a metabolic cart and venous blood samples were collected before the exercise, 15 min, and 24 h post-exercise. Serum levels of βE and BDNF were measured using ELISA kits. Data were analysed with the Mann-Whitney test, Wilcoxon signed-rank test, and Spearman's correlation. βE levels exhibited a significant increase from baseline (YA: 176±21.2 pg/ml; MA: 152.1±21 pg/ml) to 15 post-exercise (YA: 211.7±30.8 pg/ml, p<0.001; MA: 187.2±33.5 pg/ml, p<0.01), followed by a significant decline from 15 min to 24 h post-exercise (YA: 180.2±23.7 pg/ml, p<0.001; MA: 155.7±23 pg/ml, p<0.01). βE concentration before and at 24 h post-exercise was higher in YA than MA (p<0.01 and p<0.05, respectively). However, no significant differences between groups were found at 15 min post-exercise. For all time points evaluated, no correlation was observed between serum βE and BDNF levels (p>0.05). Serum BDNF levels have ...