Is a ‘runner’s high’ similar to smoking marijuana?

A “runner’s high,” or that feeling of euphoria, coupled with a decreased feeling of pain that comes at the end of a long hard run is typically attributed to the release of neurotransmitters called endorphins. But, endorphins might not be causing this euphoric state – it may be a substance called endocannabinoids.

Endocannabinoids are marijuana-like substances produced by the body that can trigger a sensation similar to a high from cannabis drugs like marijuana. Researchers came to this conclusion after determining that in mice, endorphins weren’t able to pass from the blood into the brain. However, an endocannabinoid called anandamide, which can be found in high levels of an individual’s blood after running, is able to travel from the blood into the brain.

During the study, mice were split into two groups. One group ran for five hours on a wheel while the other mice performed no physical activity. After five hours, the mice that ran exhibited less anxiety and had a higher tolerance for pain compared to those who were sedentary.

A group of mice were then given endocannabinoid antagonists, which are substances that block the cannabinoid receptors in the brain, while another group was given endorphin antagonists, which block the brain’s opioid receptors. After both groups ran for five hours, those given endorphin antagonists behaved similarly to the mice in the first study who had also run, but those given endocannabinoid antagonists were anxious and sensitive to pain.

Researchers cautioned that the findings have not been studied on humans, and whether the euphoria at the end of a long run is caused by endorphins or endocannabinoids, it’s just one of the benefits of running.

“Studies have proven that runners have a lower incidence of cancer, heart disease and diabetes, and carry less fat, have better bone density, improved mental health and usually have a healthier diet than non-runners,” says Julie Pate, running coach and yoga instructor at the Good Samaritan Health and Wellness Center in Downers Grove, Ill.

However, Pate cautions that running can become addictive.

A few signs that someone is becoming addicted include:

• Running with pain, ignoring injuries
• Running interferes with one’s job (i.e. leaving work early or going in late to accommodate running routine)
• Running interferes with one’s personal life (i.e. missing important personal events like weddings or birthdays to run, or putting the run before family members or friends)
• When skipping runs brings up feelings of fear or anxiety
• Overtraining – training when exhausted, in pain or in excess
• Loss of appetite
• Not being able to sleep
• Excessive weight loss