Marijuana and Its Effects on Athletic Performance: A Systematic Review

Objective: To determine the effects of marijuana on athletic performance. Design: We searched MEDLINE, EMBASE, CINAHL, PsycINFO, AMED, and SPORTDiscus from their beginning to September 2016. Study quality was assessed using the Cochrane collaboration tool for assessing risk of bias and the Cochrane GRADE scale. No meta-analyses were performed for this review. Setting: Subjects in a track, gym, or recreational ward. Participants: Any primary study which included male and female adults of any athletic background between ages 18 and 65, with no other comorbid conditions. Interventions: Any primary study which used marijuana cigarettes and included a control group. Main Outcome Measures: Vital signs, pulmonary measures, physical work capacity, grip strength, and exercise duration were determined to be relevant outcomes. Results: Three trials examined marijuana and its effects on athletic performance. Two trials had a high risk of bias and 1 trial had an unclear risk of bias. The effect of marijuana on outcomes including heart rate, blood pressure, and exercise duration remains unclear. Low quality evidence suggests that treatment, sham, and inactive control groups do not have a significant difference for grip strength. Low quality evidence suggests that there is an ergogenic effect of treatment demonstrated by increased bronchodilation and FEV 1 compared with inactive control and that there is an ergolytic effect of treatment demonstrated by decreased physical work capacity compared with sham and inactive control groups. Conclusion: Because the number and quality of studies was low, the effects of marijuana on athletic performance remain unclear.