A systematic review found only three trials examining marijuana's effects on athletic performance, with insufficient evidence to draw conclusions about most outcomes including heart rate, blood pressure, and exercise duration.
Athletes, sports medicine physicians, anti-doping policy makers.
Only 3 trials exist on cannabis and athletic performance - a remarkable evidence gap given the prevalence of use and its prohibited status in sports.
What the researchers found
Only three trials met inclusion criteria. Low-quality evidence suggested marijuana may increase bronchodilation but decrease physical work capacity. No significant effects on grip strength were found. The evidence for effects on heart rate, blood pressure, and exercise duration remained unclear due to study limitations.
Why it matters
Despite widespread cannabis use among athletes, the scientific evidence base for its effects on performance is remarkably thin. This review highlights a major knowledge gap in an area of significant practical importance.
The numbers in context
Only 3 trials found. Two had high risk of bias, one had unclear risk. Low-quality evidence for both ergogenic (bronchodilation) and ergolytic (decreased work capacity) effects.
How the study worked
Systematic review searching MEDLINE, EMBASE, CINAHL, PsycINFO, AMED, and SPORTDiscus through September 2016. Study quality assessed using Cochrane tools.
What this study cannot tell us
Only three studies met inclusion criteria, all with significant limitations. No meta-analysis possible due to heterogeneity. Studies were older and used smoked marijuana, which may differ from modern products.
How to read the evidence
Preliminary - systematic methodology is rigorous, but only three low-quality studies were available.
When this study was published
Published in 2018. Cannabis in sports research remains limited.
The bigger picture
Cannabis is banned in competition by the World Anti-Doping Agency, yet there is essentially no evidence it enhances performance. This disconnect between policy and evidence raises questions about the basis for cannabis prohibition in sports.
Questions still open
- Does cannabis actually impair athletic performance enough to justify competition bans? Could CBD (without THC) benefit recovery without affecting performance? Do chronic versus acute effects differ in athletes?
Common questions
Does cannabis improve athletic performance?
Why is cannabis banned in sports if there is no evidence it helps performance?
Read the original research
Marijuana and Its Effects on Athletic Performance: A Systematic Review.
Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine, 28(4), 350-357
Citation
Trinh, Kien V; Diep, Dion; Robson, Hannah. (2018). Marijuana and Its Effects on Athletic Performance: A Systematic Review.. Clinical journal of sport medicine : official journal of the Canadian Academy of Sport Medicine, 28(4), 350-357. https://doi.org/10.1097/JSM.0000000000000471
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