The Endocannabinoid System (ECS) is one of the most intriguing systems of the body. It is not completely understood yet, but the basic understanding of it is based on the network and activities of neurotransmitters that are known as endocannabinoids. These endocannabinoids fit into their specific receptors throughout the nervous system, affecting multiple processes in the body. It’s through the activity of the ECS that the cannabis plant alters the mental state; but the ECS is involved in everything from appetite to the immune system, cognition, and even memory. With recent research, scientists believe they have found a way to activate the ECS into directly improving memory with exercise.
Building upon previous animal studies which showed that exercise boosted an endocannabinoid called anandamide which has a particular affinity for improving the plasticity of the hippocampus, neuroscientists at the University of Geneva applied this working knowledge to a group of humans. The randomized group of fifteen healthy men between the ages of 18-27 years old took a cognitive assessment test for memory in which they pressed a button when the image on a screen changed in a repetitive order. This test was designed to assess the serial reaction time of participants when faced with a cognitive task.
The participants were monitored by MRI and blood levels of endocannabinoids were measured. They took the test after two separate bouts of physical activity and one period of rest (30 minutes of cycling with moderate effort, 15 minutes of high-intensity cycling with 80% max heart rate, and after rest).
The results showed that the more intensive the exercise, the more activation was seen in the hippocampus. The hippocampus is the region of the brain involved in memory and learning. Changes seen on MRI also included the activation of the brain structure called the caudate nucleus, responsible for motor skills. Likewise, the blood levels of endocannabinoids (specifically anandamide) increased the most after the high-intensity exercise.
Memory and motor skill learning was improved with all exercise regardless of intensity, but not after resting. The participants learned the sequence on the serial reaction task test significantly better after the most active and intense exercise session. The scientists believe that this trend is due in part to the rise in anandamide levels which increased the plasticity (which is the ability of neurons to exert flexibility in events of growth or reorganization) of the hippocampus.
Further studies investigating how this rise in anandamide correlates to improved memory may provide more details into how the body uses the endocannabinoids to produce feelings of well-being after exercise and for better cognitive processing.
Bosch, B., Bringard, A., Logrieco, M. et al. (2020, September 18). Effect of acute physical exercise on motor sequence memory. Retrieved January 18, 2021, from https://www.nature.com/articles/s41598-020-72108-1