What’s all this craze about CBD? What is it? And how might it help with sports pain and performance?
Cannabis has recently been getting more attention in the sports industry as a way to reduce pain and enhance recovery. In this article we will consider CBD’s, specific potential in sport and exercise based on research in physical parameters like inflammation, pain, and recovery/performance, and subjective reports of professional Rugby players whose use of CBD is highly prevalent.
CBD Products
Cannabidiol (CBD) is a non-intoxicating cannabinoid found in marijuana and hemp, and by itself is a federally legal substance, although some states still restrict its buying and selling. Remember that hemp doesn’t contain Δ-9-Tetrahydrocannabinol (THC), but marijuana does, and THC-9 is still classified as a schedule-1 drug and is federally illegal. However, many states allow marijuana to be grown, sold and/or consumed for medical and adult use. In 2018 due to evidence that CBD is safe and well-tolerated by humans (1) the World Anti-Doping Agency (WADA) removed CBD (not THC-9) from the list of prohibited substances allowing opportunities to explore CBD in the world of sports and performance.
In preclinical trials (which means not with humans) CBD is positively associated with reducing inflammation, pain, anxiety, and tumor growth (2). Its known side effects in humans are fatigue, diarrhea, and changes in weight/appetite (3). In human studies of CBD and children with intractable epilepsy (4), CBD has been demonstrated to be highly effective in significantly reducing seizures and is now available with a prescription to treat childhood epilepsy. CBD comes in many forms such as tinctures, capsules, topical lotions and creams, essential oils, edibles, and flowers, and can be found as an additive to a wide range of products including coffee, sodas, lip balm and shampoo (check out our list of Cannabis Terms for any unfamiliar words).
CBD and Sports
Athletes put their bodies under lots of stress during training which can lead to injury, soreness, and inflammation and ultimately decrease their performance. While over-the-counter medications like ibuprofen and naproxen help to mitigate pain and inflammation, they increase risk of gastrointestinal ulcers, heart attack, and kidney disease (5). This may be reason for many athletes turning to a plant-based, more ‘natural’ approach with CBD.
Inflammation
In sport and exercise, inflammation, pain, recovery, and performance can each affect one another. Many athletes train to enhance their performance with high-intensity and/or high-resistance workouts that can cause damage to their muscle fibers, a condition known as exercise-induced muscle damage (EIMD). When EIMD, or any other injury occurs, all types of cells (i.e. neutrophils, lymphocytes, etc.) and pro-inflammatory cytokines (i.e. interleukin (IL)-6, IL-8, tumor necrosis factor (TNF-a) flood the area causing inflammation. While inflammation is part of the healing process its presence is painful and it can interfere with proper movement mechanics which will interfere with performance and can cause additional injury (6). We already know many athletes use ibuprofen to manage inflammation and pain, but now let’s see if CBD can affect inflammation.
The endocannabinoid system (ECS) interacts with all our biological systems and includes CB1 and CB2, receptors which are highly expressed in the peripheral nervous system. (See our previous article for more details about the ECS). CBD appears to modulate CB2 receptors as well as the vanilloid TRPV1 receptors of the immune system, both of which are involved in inflammation. The result is that pro-inflammatory cytokines and neutrophils are inhibited, and anti-inflammatory cytokines are released, resulting in a decrease in inflammation (6,7,8). Anti-inflammatory effects are stronger with higher doses of CBD, however lower doses can still be effective (6,8). Assuming this preclinical research applies to humans, this would be very beneficial for overworked athletes
Pain
Pain is often associated with inflammation and CBD’s effect on TRPV1 receptors appears to be helpful in reducing pain (6,8). Because TRPV sensitization is also involved in delayed onset muscle soreness (DOMS), which can occur with strenuous exercise, it is possible that CBD could be provide pain relief by modifying TRPV if DOMS was to occur (6). Indeed, in a study of healthy, young adults, who underwent training to induce EIMD and DOMS, those who consumed CBD had significantly less pain 24 and 72 hours later whereas those who took medium chain triglycerides (MCT) oil or did nothing reported little to no change in pain (9).
Pain is also a symptom of osteoarthritis (OA), which is a degenerative disease of the joints that causes pain and stiffness and can include swelling or inflammation especially after a lot of activity. In a study of rats with OA who were treated with CBD, researcher suggested that there might be other mechanisms for CBD’s pain-relieving effects (10). After simulating OA in one joint, pain was assessed by measuring the firing of afferent nerve fibers, which carries sensory information (including pain) to the brain and watching the behavior and movement of the rats.
Then, researchers then gave the rats CBD in different dosages and observed their afferent firing and behavior.
Afferent firing:
○ Results: CBD caused a reduction in afferent firing, indicating that less pain information was sent to the brain. A significant dose-dependent relationship was observed with a lower CBD dose being effective for reducing pain and a higher dose being even more effective, with a decreased firing by an average of 22.8%. That’s huge!
Behavior:
○ Results: High dose CBD reduced pain behaviors that including paw withdrawal and paw licking, and improved the rats’ willingness to bear weight on the arthritic limb. Low dose CBD did have result in any behavior change.
Now that we know CBD has significant implications for inflammation and pain sensitivity, let’s consider CBD in recovery and performance.
Recovery and Performance
Some researchers have suggested that high levels of some biochemical markers such as creatine kinase (CK) and myoglobin (Myo) are associated with the muscle damage that can occur with high-intensity strength training and activity. CBD has been investigated for pro-regenerative and performance effects in a couple of studies with inconclusive results. In a double-blind, placebo-controlled the effects of CBD on CK and Myo were measured before and after the participants consumed either CBD or a placebo for 3 consecutive days after intensive training (11). Here are the results for recovery and performance.
● Recovery: After significantly increasing, CK and Myo levels decreased 2 days after training in the CBD and placebo groups, however, CBD provided greater benefit for recovery at 72 hours.
● Performance: When using a repetition max test to determine strength, there was such a wide range of performance among the participants that it’s unclear what real effect CBD might have on muscular strength following intensive training.
At this time researchers can’t explain the variability of performance seen when people consume CBD, however, it might be explained by different absorption rates based on metabolism, stomach contents, etc. Obviously more research must be done, but let’s see what the athletes themselves have to say.
Sport and Subjective Reports - Rugby
Rugby is a sport with lots of intensity and impact so it’s no surprise that there’s a high prevalence of CBD among its players. Researchers have found that across 25 different UK rugby teams and 517 players 26% currently use or have used CBD for recovery/pain (80%), sleep (78%), anxiety (32%), and other medical purposes (14%) (12). Most of theplayers report benefit from CBD (67%) including improved sleep (41%), recovery/pain (14%), mood (6%), anxiety (3%) and other medical concerns (8%). Although the number of those who experienced improved recovery/pain (14%) was considerably lower than the number of individuals used CBD for those purposes (80%), no player reported any perceived adverse effects from CBD. The risk of adverse effects while taking CBD is largely unknown, it doesn’t appear to be an issue for this athletic community.
Limitations and Drawbacks in Sport
Although CBD is generally safe in comparison to many over-the-counter and prescribed medications, it does have potential side effects include fatigue, diarrhea, and changes in appetite/weight (3), all of which may interfere with athletic training and sport. Nevertheless, animal trials have given us some promising evidence that CBD is helpful for reducing inflammation and pain, and in humans, shows promise for treating DOMS. Further research is needed to determine if using CBD is worthwhile for enhancing recovery after intense training and competition and if it can play a role in athletic performance. Now that CBD is legal and its side effects are generally mild, we will hopefully see more human studies about its potential use and benefits.
Right now, however, it's important to remember that although CBD is legal, its production is not well-regulated. Products may contain unlabeled illegal substances like THC or harmful chemicals like pesticides or heavy metals which can contribute their own adverse effects and pose a threat to both athletes and other users (3). For these reasons, along with CBD’s association with marijuana, some sports associations still advise against its use (12).
Is there more?
As seen in the study of rugby players, athletes may be looking to CBD for more than the physical concerns of pain, inflammation, soreness, and recovery. With the psychological demands of training and competition, interventions for mood, anxiety, stress, and sleep disorders are often desired.
Our next article, coming out soon, will focus on the mental effects of CBD in athletes and sport.
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Isenmann, E., Veit, S., Starke, L., Flenker, U., & Diel, P. (2021). Effects of Cannabidiol Supplementation on Skeletal Muscle Regeneration after Intensive Resistance Training. Nutrients, 13(9), 3028. https://doi.org/10.3390/nu13093028
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