In 2018 the World Anti-Doping Agency (WADA) removed cannabidiol (CBD) from its list of banned substances and since then there has been an apparent explosion of interest in the stuff, with elite and recreational athletes alike reporting on the benefits they have seen in their recovery and performance as a result of it. But what is it, what do we really know of its benefits in exercise, and are there any risks in taking it?

What is it?

CBD is not cannabis!! It is a similar compound – one of over 100 cannabinoids found in marijuana or hemp plants. Unlike cannabis, CBD does not have psychoactive properties … so no high when you take it! Whilst CBD is no longer banned by WADA, cannabis and other cannabinoids remain so.  CBD oil is either taken orally as drops from a vial, as a balm, or smoked. 

CBD in the body

Like cannabis and other cannabinoids, it appears to impact many signals in our body … relating to everything from anxiety through to inflammation.  

The science bit! What we seem to know is that CBD impacts the endocannabinoid system, antagonizing at least one of the two main receptors in this system (the CB1 receptor) to reduce the strength of signals in this system in both the central nervous system and peripheral tissues. The endocannabinoid system is involved in many functions in the body, including pain, memory, mood, motivation and motor function. CBD also appears to modulate certain opioid receptors, ion channels, transcription factors, and enzymes that are involved in not only pain responses, but also muscle relaxation, inflammatory and antioxidant responses. 

However, mechanisms at the cellular level do not always translate to what happens in the body as a whole. 

So, what does the research say? From research to date, there is some evidence that CBD can reduce chronic neuropathic pain in adults, reduce anxiety in individuals with anxiety disorders, improve sleep in individuals with certain sleep and chronic pain disorders, and improve spasticity symptoms associated with multiple sclerosis. In animal models, CBD has also been shown to reduce the inflammatory response and promote an antioxidant response.

What about exercise?

You may be surprised to learn that despite the growing popularity, little research has been performed on the impact of CBD oil on exercise performance and recovery!! This is driven by the fact that until recently it was a banned substance. 

Much of the ‘evidence’ is from the testimonials of those who have tried CBD oil, or from extrapolation of the studies performed in the animal models and disease states stated above. Extrapolation from animal or disease models is not necessarily valid, as the body can function quite differently in normal healthy humans … in the same way that the response of trained and untrained individuals to a supplement can be very different! Testimonials are both reliable and unreliable – there is the potential for a placebo effect (which nonetheless can be a true response that can aid performance!), but also the potential to gain insight from controlled case studies. 

Based on what we know of the cellular mechanisms of CBD, testimonials, animal and disease models, there are several ways that CBD may benefit exercise. These are:

  • As a supplement to reduce anxiety, increase alertness, and increase risk taking behaviour to improve confidence and responsiveness, and so performance

  • As a muscle relaxant, analgesic, anti-oxidant and anti-inflammatory to reduce delayed onset muscle soreness and accelerate recovery post exercise 

But we must remember that these must be scientifically tested in the field and in the lab before any reliable conclusions can be drawn!! When we consider the anti-oxidant and anti-inflammatory responses, we must also consider the fact that there is evidence that both the inflammatory and oxidative stress response are required for long term training adaptations, i.e. to improve long term performance. There is the risk that by taking CBD oil we may be improving short term performance at the expense long term performance. As such, CBD oil may be something to use in acute multi day competition settings to aid performance, but may need to be used with caution day to day. But again … we do not know until we study it directly!!

What else to consider?

CBD is a plant extract and it is very difficult (nigh on impossible) to obtain 100% pure CBD without the cost being astronomical. This means the CBD oil you buy inevitably contains other compounds. Whilst CBD has been removed from the WADA list of banned substances, cannabis and other cannabinoids remain on it. A study published in 2017 in the Journal of the American Medical Association found that 1/5 of CBD products they tested contained THC, the psychoactive (and banned) component of marijuana. If anyone who is a competitive athlete subject to drug testing is taking CBD oil, it seems likely that it is important they confirm the purity and composition of what they are taking. 

This same study found that less than 1/3 of the CBD products they tested contained the amount of CBD claimed. Considering that we have already highlighted that it may be difficult to take in enough CBD to be useful, this may mean that some commercial CBD products have very little effect in the body. 

The World Health Organization (WHO) wrote in 2017 that "cannabidiol does not appear to have abuse potential or cause harm”, although few long term studies have been performed to really be able to conclude this. Although this can also be said of many supplements on the market.

Conclusion …

I think this is a ‘watch this space’ one, as it does sound like there could be potential benefits of CBD use for athletes. However, more research is needed. In particular, whether short term anti-inflammatory effects negatively impact long term training adaptations and performance and / or whether any potential negative effect is outweighed by the positive effect of faster recovery, enhanced alertness and increased motivation that enable an athlete to train harder therefore inducing greater training adaptations to enhance performance. It will be interesting to see what the coming years reveal!! 

Read more …

National Academies of Sciences, Engineering, and Medicine (NASEM); Health and Medicine Division; Board on Population Health and Public Health Practice; Committee on the Health Effects of Marijuana (2017). An Evidence Review and Research Agenda. The Health Effects of Cannabis and Cannabinoids: The Current State of Evidence and Recommendations for Research. Washington, DC: National Academies Press

Vuckovic, S, Srebro, D, Vujovic, KS, Vucetic, C and Prostran, M. (2018). Cannabinoids and Pain: New insights from old molecules. Frontiers in Pharmacology. 9:1259.