Alleviating depression: exercise and the endocannabinoid system


Beneficial links between exercise and the endocannabinoid system are coming to light thanks to new research.

Besides just the physical benefits of exercise, for centuries we have known the beneficial psychological impact of exercise. Scientists know that exercising daily is a great way to alleviate symptoms of depression however, how it does this has never been clear. Now it seems that the answers may be found in the link between exercise and the endocannabinoid system.

The system is made up of the body’s own naturally occurring cannabinoid molecules and their receptors and activation of these receptors appears to strengthen connections in the brain, as well as possibly influencing pain and depression.

In a new study, Jacob Meyer, an assistant professor of kinesiology at Iowa State University, and researchers at the University of Wisconsin-Madison, Medical College of Wisconsin and William S. Middleton Memorial Veterans Hospital, measured endocannabinoid levels and changes in mood before and after exercise sessions with varying levels of intensity.

The study found that subjects experienced a significant boost in endocannabinoids and improvements in mood following prescribed moderate-intensity exercise.

Exercise and the endocannabinoid system

Data from 17 women who suffer with depression was analysed during the study, where each woman completed two, thirty-minute exercises on stationary bikes at both moderate and preferred intensity. The data showed that both sessions on the bike improved mood, but only showed an increase in endocannabinoid levels for moderate intensity exercise. There was no difference for preferred intensity.

Meyer said that the differences may stem from variation in the preferred session because some women who were participating stayed consistently at a lighter intensity for their preferred option, whereas other women completed intervals. Meyer emphasised that with a small sample, the variation may have obscured the relationship between the preferred intensity exercise and the endocannabinoid system changes.

Prescribed v preferred exercise

The study also shows there is some correlation between prescribed exercise and increase in mood, as opposed to preferred exercise. Meyer and his team completed a similar study in 2016 that looked at the effect of exercise on brain-derived neurotrophic factor or BDNF, a protein that regulates neuron growth and survival. People with depression typically have lower levels of BDNF.

The 2016 study found that when women with depression were prescribed an exercise session similar in intensity to exercise they selected, their BDNF levels were significantly higher following the prescribed session. Meyer said: “Having someone else prescribe the exercise could be involved in both the psychological and biological response to exercise.”

Effects appear to be long-lasting

The study suggests that the endocannabinoid system changes were significantly related to the improved mood up to 30 minutes after the moderate exercise. During each session, researchers collected blood samples immediately after exercise and measured mood and anxiety at 10 minutes and 30 minutes post-workout.

Meyer said: “These results show us that the effect of prescribed moderate-intensity exercise on mood is generally pretty quick and lasts for a while at a relatively sustained rate. However, given that people felt better after the preferred exercise session, even though it didn’t change endocannabinoid levels, multiple factors are likely involved in how exercise makes people feel better.”

Alternative treatments for depression

Through discovering the links between exercise and the endocannabinoid system, the goal is to develop new treatments for mental health conditions that include exercise. Meyer is currently recruiting 20-to-60-year-old men and women to participate in the study and says understanding the link between mood, exercise and the endocannabinoid system could lead to better treatment options.

“Finding alternatives to medication is important for the treatment of depression,” Meyer said. “If we can figure out how exercise works with the endocannabinoid system, we could then design optimal exercise interventions.”


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