Podcast, Science and Physiology

CBD for endurance athletes with Christian Cheung, MSc | EP#351

 August 15, 2022

By  Bernardo Gonçalves


Christian Cheung - That Triathlon Show

Christian Cheung is a PhD student and researcher in the Human Performance and Health Research Laboratory at the University of Guelph, Canada. Christian's current research is focusing on the use of cannabis and cannabinoids, like CBD, in endurance sports. In this interview, we discuss the evidence for efficacy and safety of CBD and cannabinoids, as well as important anti-doping perspectives.

In this episode you'll learn about:

  • Cannabis, cannabinoids, CBD and THC: known effects and use cases in general and in sports
  • CBD and its effects on sleep and anxiety, pain and inflammation, and neuroprotection
  • Anti-doping considerations of CBD products and cannabinoids
  • Different types of CBD consumption modes and dosage
  • Practical recommendations for endurance athletes

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Christian background

02:57 -

  • I am a researcher and PhD student at the Human Performance and Health Research Laboratory at the University of Guelph, Canada.
  • My research is on understanding how individuals adapt to training and how different stimuli perturb physiology.
  • My topic of research is cannabis and cannabinoids.

The definition of cannabis and cannabinoids

03:40 -

  • Most people know cannabis as a recreational drug.
  • It is a plant associated with a euphoric high when inhaled or ingested.
  • They have some molecules unique to the plant called photo-cannabinoids.
  • We have also molecules called exogenous cannabinoids within our bodies, but the group of molecules associated with the plant would be cannabinoids.
  • CBDs are an acronym for cannabidiol, one of the most abundant cannabinoids in cannabis plants.
  • CBD research shows that it can have benefits without psychological effects. In contrast, THC (the other most prominent cannabinoid within cannabis) associates with a high.
  • These cannabinoids are the discussion in athletic research and implementation.

General effects of cannabinoids on the human body

05:49 -

  • We still do not understand how these molecules react with all body tissues. So, we can talk about the effects of CBD and THC on the brain, but these might have multi-organ effects that we are still trying to understand.

Legislation on the use of cannabis

06:45 -

  • In 2018, Canada legalised the recreational use of cannabis, and the government now sell it.
  • People over 19 years old can go to a cannabis store and buy a specific cannabinoid or cannabis product.
  • However, this does not happen in most places.
  • There are different legislation levels in the USA, variable region by region.
  • For most regions, this is still an illegal drug.

Effect of cannabis and THC on athletic performance

08:27 -

  • The review we did was to give practitioners, athletes and coaches a starting point to understand where these molecules sit in the context of athletics.
  • There is little research on the use of cannabinoids on exercise performance, using methodologies associated with sports research.
  • We have studies on how cannabis and THC affect exercise performance. However, much of the literature comes from clinical environments that are not doing exercise like regular athletes might be doing.
  • We talk about patients with coronary artery disease, and exercise capacity reduces with prior THC consumption in those populations.
  • We do not know the effects on athletes because an athlete will fail much later in a test to exhaustion than a person of those populations.
  • Research has looked at physiological effects in those populations, and the most prominent effect of the use of THC and cannabis is the increase of HR at submaximal intensity.
  • For example, a person might have an HR at 100 bpm when doing 100 W without cannabis. At the same time, that person might have a 20% HR increase when consuming cannabis containing THC.
  • However, the response to maximal exercise remains the same.
  • Moreover, THC is a prohibited substance to consume according to the anti-doping legislation.

CBD and sleep

12:34 -

  • Sleep and anxiety might be two reasons athletes consume CBD because CBD products market those effects.
  • Much research on using CBD as an anti-anxiety and sleep-promoting product has come from animal research or pre-clinical research models. There is not much human data yet, but it shows some promising results.
  • CBD might help with anxiety the researcher puts in the experiment: public speaking or mental math challenges.
  • There have been some reports of sleep improvements in some selective populations.
  • From a sleep perspective, there is no research showing CBD is beneficial.
  • Athletes should consider if it will work for them and the potential risks associated with CBD use.
  • For someone sleeping well, it will be challenging to improve even more their sleep compared to someone that has impaired sleep.
  • Moreover, the results of sleep effects come from subjective scores and not so much from physiological data.
  • Therefore, CBD use might be more important for someone struggling with a problem than to optimise regular functions.
  • Nevertheless, we should only consider all the benefits we might have with CBD use if we already have optimal training, nutrition and recovery practices.

Pain, inflammation and muscle function

16:33 -

  • Within the research community, this area has been of much interest lately.
  • CBD might help reduce pain, and it is a potent anti-inflammatory agent.
  • There are many interventions to reduce inflammation or improve recovery.
  • One way to test CBD efficacy is by damaging muscle with exercise and evaluating how CBD can potentially help with the subjective perspective of damaging exercise or recovery to perform another task after exercise.
  • Three studies looked at the efficacy of CBD in reducing muscle damage.
  • Most have some damaging exercise, an exercise test and a blood test to understand how well the inflammatory response lowers with CBD.
  • The findings have been inconsistent, but we see that the inflammatory response from exercise can get lower with CBD use.
  • However, the effect size has not been that significant.
  • When we look at 24 and 48h after exercise, we do not see differences in anti-inflammatory response. One study found a reduction in anti-inflammatory markers after three days.
  • However, the other studies have not shown those results. Nevertheless, there is some room to understand if CBD can have some use as a recovery aid.
  • We must also be aware of the context where you will be a supplement. All the trials were acute studies instead of continuous evaluations over a specific period.
  • In training, inflammation can be a positive thing because it can lead to better adaptations occurring in the body.
  • For example, we will not do ice baths every day, but only we need to recover in between events or tapering for an event.
  • Context is crucial when discussing CBD.

Concussion and neuroprotection

22:18 -

  • My collaborators did a trial on using CBD in rugby leagues, and they showed a high CBD usage because of sleep and anxiety but also when considering neuroprotection.
  • Some of the evidence for using CBD is when we use CBD in a preventive measure, which is not the method people suggest using CBD at this point.
  • It might not be wise always to have anti-inflammatory signals. 
  • There is potential to have neuroprotective properties, but we do not know the impact on training.
  • Therefore, CBD is not something I would not recommend at this point with the evidence we have and the context of considering nutrition and implementation in their daily lives.

Best methods to supplement with CBD

24:11 -

  • I am not a specialist in pharmacology, but there is a lot to consider when consuming CBD.
  • Where CBD is legal, you can get it through drops, oil, shot, or some oral consumption method, or you might inhale it.
  • The methods we use will impact how well CBD enters the body.
  • Inhalation would be the best method to get CBD, followed by the shots and oils, and the worst way would be by eating it because we have to digest it and metabolise it.
  • Therefore, you should also consider the dose size within each method. Oral ingestion might not be the most efficient but have a larger dose.

Risks of CBD supplementation

27:07 -

  • The risks of CBD supplementation are relatively low.
  • It seems a mild and well-tolerated drug in the doses that would be available to the consumer.
  • Therefore, you should consider your dose in the broader spectrum. 
  • Some studies use 100s mg of CBD, which will be well-tolerated.
  • Then, consumer-available doses will be in the 10s mg.

Why CBD is not a prohibited doping substance

28:56 -

  • I think we will revisit this question in the following years as cannabis becomes more accepted.
  • WADA bans products because they might be unsafe, improve performance, or be against the spirit of sport.
  • Most available cannabinoids are not allowed because there might have been much research on the area, and it is an illicit substance, which allows WADA to consider that it is against the spirit of sport.
  • CBD is not a prohibited substance because research shows that it seems to be well-tolerated by people and is not psycho-active.
  • Therefore, it has detached from an illicit drug.

CBD contamination risks

32:18 -

  • Even though supplements might say it is CBD, the product is risky. There are so many cannabinoids out there that probably CBD supplements might contain traces of them.
  • Some research has shown that some CBD products contain inaccurate amounts of other cannabinoids.
  • In areas where CBD is not regulated, we do not have the best trials to test all the labels.
  • In Canada, athletes can have more confidence labels due to the higher controls.
  • Therefore, athletes should consider if the small benefit of CBD outweighs the risk of contamination and a positive anti-doping test.
  • Most samples of CBD products tested have cannabinoids not stated, many were not labelled, and some would trigger anti-doping violations.
  • Getting CBD in the purest form might be difficult.
  • I do not think this study's CBD products were Informed-Sport certified.
  • Identifying washout periods below specific thresholds will not be an exact science, and it will vary between people.
  • Cannabis contains over 100 cannabinoids. (all of them illegal except for CBD)
  • The washout period will vary for each cannabinoid. For example, THC is fat soluble, so it tends to remain in the body. Nevertheless, this cannabinoid has a threshold, so trace amounts are not a problem.
  • However, some cannabinoids can remain in the body for days/weeks.
  • Using CBD products in competition periods is more complex because timing is essential. Multiple weeks with CBD supplementation before the event are necessary to ensure you would not have problems.

Christian's recommendations for athletes

38:08 -

  • It is not clear that CBD is beneficial.
  • Assuming it is legal and safe, it could be worth trying if the CBD benefits would benefit you.
  • With that said, I would only recommend CBD use if we have controlled placebo studies where we can show the benefits and the improvements of using them.
  • If anti-doping controls are your worry, you should be much more hesitant when taking these products.
  • At the moment, we are not sure if the positives outweigh the risks of CBD.

What product athletes should consider for taking CBD

40:09 -

  • I would consider the dosage of the products. If you are an athlete looking for a product to give you benefits, you should consider the product's dosage.
  • For example, some CBD drinks market 5 mg of CBD in it. If the studies showing potential benefits are using 100s mg of CBD, we should not invest in such a product.
  • If there are benefits, we need to have the appropriate doses to see them.
  • You want to get a regulated source to know what is in it.
  • I would critically evaluate the cost/benefit ratio.

Christian's current and future projects

41:50 -

  • Our research wants to cover some knowledge gaps in the relationship between cannabis and sports.
  • We want to understand how cannabinoids affect the response to exercise.
  • We are finishing a project evaluating how cannabinoids and their different dosages impact cardiovascular function, the response to exercise and the performance impacts.
  • That way, we have a starting point to understand how athletes should consider these drugs.

Rapid-fire questions

43:44 -

What is your favourite book, blog or resource?

Endure: Mind, Body, and the Curiously Elastic Limits of Human Performance Hardcover by Alex Hutchinson

What is an important habit that benefited athletically, professionally or personally?

Consistency and taking care of myself.

Who is someone you have looked up to or who has inspired you?

I had the luck to spend much time with my grandpa as a kid, and he was an engineer that would run science experiments for me as a child.


Bernardo Gonçalves

Bernardo is a Portuguese elite cyclist and co-founder of SpeedEdge Performance, a company focused on optimising cycling and triathlon performance. He writes the shownotes for That Triathlon Show, and also produces social media content for each new episode.

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