Cannabidiol (CBD) is one of many non-psychoactive molecules found in the cannabis plant. Some recent reports suggest that CBD can produce modest reductions in symptoms of anxiety and psychosis when relatively high doses (300 to 1,500 mg) are consumed. In contrast, the typical oral CBD dose for people with chronic pain ranges between 2 and 40 mg. Acute oral doses up to 6,000 mg appear to be safe and well-tolerated, although subjects often report having diarrhea, nausea, and headache.
Recently, over-the-counter oral CBD has been marketed specifically to athletes, particularly in the U.K., Canada, and the U.S. Its use by athletes has been facilitated by its recent removal from the World Anti-Doping Agency’s “Prohibited List.” The most common reasons for use by athletes were to enhance recovery, improve sleep (unfortunately, CBD worsens sleep quality), and reduce anxiety.
A recent randomized, placebo-controlled pilot study investigated the effects of acute, oral CBD (300 mg) on physiological and psychological responses to submaximal and exhaustive running exercise in endurance-trained males.
Exercise elevated plasma AEA concentrations. AEA is an endogenous cannabinoid that is typically produced by the body in response to endurance exercise. AEA has analgesic and anti-inflammatory actions that are intended to repair exercise-induced injuries. The oral CBD treatment reduced the plasma level of AEA. This effect is expected. High doses of CBD will accelerate the metabolism of endocannabinoids.
Exercise increased the serum concentrations of various biomarkers of systemic inflammation, muscle damage, and gastrointestinal damage. The elevation of these indicators of bodily injury is typical following endurance exercise. Oral CBD appeared to suppress the exercise-induced increase in pro-inflammatory proteins. Unexpectedly, oral CBD may have increased the degree of muscle damage associated with exercise. Oral CBD slightly increased VO₂ max, which is a measure of how much oxygen the body absorbs and uses while exercising.
The authors concluded that any detrimental effects of CBD on running efficiency are small and unlikely to impair aerobic exercise performance. CBD appeared to improve self-ratings of pleasure during the first 40 minutes of submaximal exercise. CBD may improve affect during exercise via its actions at various brain and body receptors that are involved in mood regulation and analgesia. No serious adverse events occurred during this investigation.
These preliminary results suggest that acute, oral CBD may alter key physiological and psychological responses during aerobic exercise. Its effects on VO₂ max, feelings of pleasure during exercise, and exercise-induced inflammation require additional future investigations. The absence of obvious detrimental effects suggests that CBD is unlikely to impair aerobic exercise performance in endurance-trained males and may therefore have value within the sporting context.