Many people have experienced reductions in stress, pain, and anxiety after exercising. What is behind the so-called 'runner's high'? There is new research on the neuroscience of exercise.
The runner's high has been attributed to a drug. These chemicals are produced in the body of humans and other animals after exercise and in response to stress.
New research from my lab summarizes the work done on this topic. We found that exercise increases endocannabinoids in the body, which is a process called " homeostasis." The benefits of exercise on the brain and body may be explained by this natural chemical boost.
I work at the Wayne State University School of Medicine. My lab studies brain development and mental health, as well as the role of the endocannabinoid system in stress regulation and anxiety disorders in children and adolescents.
This research has implications for everyone who exercises with the aim of reducing stress and should serve as a motivator for those who don't.
There are health benefits of exercise.
Exercise is beneficial for physical health. There is a correlation between varying amounts of physical activity and reduced risk of premature death and many chronic health conditions.
Over the past two decades, mounting research shows that exercise is beneficial for mental health. Regular exercise is associated with lower symptoms of anxiety, depression, Parkinson's disease, and other mental health or neurological problems.
Better cognitive performance, improved mood, lower stress, and higher self-esteem are all linked to consistent exercise.
It is not clear what is behind the mental health boost. We know that exercise increases metabolism, blood flow, and the release of chemicals in the brain, as well as promoting the formation of new brain cells.
Some of the chemicals are called neurotrophic factors. Changes in activity of brain cells are related to learning and memory.
Scientists have shown that exercise increases blood levels of a natural pain killer. Opioids help to relieve pain by working in the brain.
The belief that the endorphin release is related to the runner's high is based on early research.
Scientists have long questioned the role of endorphins in the runner's high sensation because it can't cross into the brain through the blood-brain barrier, which protects the brain from toxins and pathogens. The beneficial effects of exercise on mood and mental state are likely to be driven by other factors.
Our research and that of others show the role of our body's natural versions of cannabinoids, called endocannabinoids.
You may be familiar with the compound in cannabis known as cannabinoids, which can cause people to feel high. Cannabidiol, also known as cannabidiol, is an extract of cannabis that is used in many products.
Humans also make their own versions of endocannabinoids, which many people don't know about. These are tiny molecule made of fats that circulate in the brain and body, and "endo" refers to those produced in the body.
The cannabinoids work in the brain and body. They cause a number of effects, including pain relief, reduction of anxiety and stress, and enhanced learning and memory.
They affect hunger, inflammation, and immune functioning. The levels of endocannabinoids can be influenced by a number of factors.
It's important to note that one shouldn't go for a run or bike ride if they want to smoke or eat cannabis. The effects of getting high on the brain are not as bad as with endocannabinoids.
The endocannabinoids are the star players in the runner's high according to studies.
The studies show that people still experience euphoria even when they are not using a drug like naltrexone. The studies showed that blocking the effects of cannabinoid receptors reduced the benefits of exercise.
Several studies have shown that exercise increases the levels of endocannabinoids in the blood, but some have reported inconsistent findings or that different endocannabinoids produce different effects.
We don't know if all types of exercise produce the same results. It is an open question if people with and without health conditions can experience the same endocannabinoid boost.
The impact of exercise on endocannabinoid levels was addressed by an undergraduate student in my lab.
We compared the effects of an acute exercise session with the effects of a chronic program, such as a 10-week running or weightlifting program. Different levels of exertion could have different effects on the endocannabinoids.
We found that exercise boosted endocannabinoid levels. The effects were most consistent for anandamide, a chemical messenger which was named after it's positive effects on mood.
We observed a boost in endocannabinoids across different types of exercise, including running, swimming, and weightlifting, for people with and without health conditions.
Although only a few studies looked at intensity and duration of exercise, it appears that moderate levels of exercise intensity are more effective than lower-intensity exercise when it comes to raising endocannabinoid levels.
It is important to keep your heart rate elevated for at least 30 minutes to reap the full benefits.
There are still questions about the effects of exercise on endocannabinoids. We didn't see consistent effects on resting endocannabinoid levels from a six-week cycling program.
It's not clear what the minimum amount of exercise is to get a boost in endocannabinoids, and how long these compounds remain elevated after acute exercise.
The findings bring researchers one step closer to understanding how exercise benefits the brain and body. During the rush of the holidays, they offer an important motivator for making time for exercise.
Hilary A. Marusak is an assistant professor at Wayne State University.
The Conversation's article is a Creative Commons licensed one. The original article can be found here.
