School of Anthropology, University of Arizona, Tucson, AZ 85721, USA.
Eur J Appl Physiol. 2013 Apr;113(4):869-75. doi: 10.1007/s00421-012-2495-5. Epub 2012 Sep 19.
Endocannabinoids (eCB) are endogenous ligands for cannabinoid receptors that are densely expressed in brain networks responsible for reward. Recent work shows that exercise activates the eCB system in humans and other mammals, suggesting eCBs are partly responsible for the reported improvements in mood and affect following aerobic exercise in humans. However, exercise-induced psychological changes reported by runners are known to be dependent on exercise intensity, suggesting that any underlying molecular mechanism should also change with varying levels of exercise intensity. Here, we examine circulating levels of eCBs following aerobic exercise (treadmill running) in recreationally fit human runners at four different intensities. We show that eCB signaling is indeed intensity dependent, with significant changes in circulating eCBs observed following moderate intensities only (very high and very low intensity exercises do not significantly alter circulating eCB levels). Our results are consistent with intensity-dependent psychological state changes with exercise and therefore support the hypothesis that eCB activity is related to neurobiological effects of exercise. Thus, future studies examining the role of exercise-induced eCB signaling on neurobiology or physiology must take exercise intensity into account.
内源性大麻素（eCB）是大麻素受体的内源性配体，在负责奖励的大脑网络中高度表达。最近的研究表明，运动激活了人类和其他哺乳动物的 eCB 系统，这表明 eCB 部分负责报告中的情绪改善和有氧运动后的影响。然而，跑步者报告的运动引起的心理变化已知取决于运动强度，这表明任何潜在的分子机制也应该随运动强度的变化而变化。在这里，我们在四个不同强度下检查了休闲跑步者在有氧运动（跑步机跑步）后循环中的 eCB 水平。我们表明，eCB 信号确实与强度有关，只有在中等强度下才会观察到循环 eCB 的显著变化（非常高和非常低的强度运动不会显著改变循环 eCB 水平）。我们的结果与运动时与强度相关的心理状态变化一致，因此支持 eCB 活性与运动的神经生物学效应有关的假设。因此，未来研究检查运动诱导的 eCB 信号对神经生物学或生理学的作用时，必须考虑运动强度。
