Marijuana and Lifting Weights: What the Science Suggests

As of June 30, 2021, there are 19 states where recreational marijuana is legal. Medicinal marijuana or CBD oil is legal in an additional 28 states. According to a 2019 National Survey on Drug Use by the US Dept. of Health and Human Services, 46 percent of adults in the USA have used marijuana.

The use of marijuana — or at least the discussion surrounding it — is becoming less of a taboo topic across the U.S. We’re seeing states become much more liberal with how they view the use of cannabis. More athletes use marijuana to improve performance, support recovery and even help consume their goal calories. So that begs the question: does marijuana help improve athletic performance?

Image via Shutterstock/Jono Erasmus

This article will dive into what cannabis actually is, how it affects the body, where it currently stands with the World Anti Doping Agency (WADA), and what science says about its use and lifting weights.

Editor’s Note: This article is intended to provide an objective view of using cannabis and lifting weights. We’re not endorsing the use or promoting marijuana’s use, especially since it’s still illegal in many countries globally and many states across the U.S. Please abide by all local and federal laws, as well as the rules of any sporting bodies where you compete.

Background of Cannabis or Marijuana

Cannabis, also known as marijuana (among other names), is a psychoactive drug from the cannabis plant. There are three types of cannabis plants: Cannabis Sativa, Cannabis Indica, and Cannabis Ruderalis.

Brief History of Cannabis

The cannabis plant originates from Central and South Asia, and its first use dates way before Western Society began using this psychoactive drug. To provide a brief history of cannabis, its first documented use was in 2727 B.C. with Chinese Emperor Shen Nung. Since then, there have been multiple accounts and suggestions of Egyptian mummies having cannabis fragments buried with them. In addition, some historians believe that the ancient drug ‘soma’ was actually cannabis as we know it today.

It wasn’t until the mid-1500s when cannabis made its way to Western Society as the Spanish began to import hemp from Chile. Hemp is a variation of the cannabis Sativa plant and is often used for commercial, industrial purposes. At the time, hemp was used to create rope and fiber.

Marijuana’s Effects On the Body?

Marijuana contains multiple active compounds, but the main psychoactive chemical in cannabis is tetrahydrocannabinol (THC). The mental and physical effects on the body are colloquially known as being “high” or “stoned.” Those effects, which vary depending on the specific strand of marijuana, can include a feeling of altered perception, heightened mood, increased appetite, and sometimes a sense of euphoria.

Cannabinoids, in short, are chemical compounds that interact with our body’s cannabinoid receptors. These cannabinoid receptors as part of the central nervous system, including the brain. Along with the receptors are their respective ligands, which function as triggering molecules for protein binding. Together, these make the Endocannabinoid System. (1) The Endocannabinoid System plays a role in our brain’s reward system that is linked to drug use and is often linked to causing psychiatric disorders. However, it can also improve them with carefully planned manipulation.

Another factor that can contribute to the “high” feeling that comes with cannabis use is dopamine. This neurotransmitter plays a role in our body’s reward system, which cannabis has been seen to influence to an extent. Cannabinoids have been suggested to increase dopamine concentrations in the body and vary depending on the strand. 

These are only two pieces of the puzzle of what marijuana does to the body. Many other factors have a role in this drug’s use and our body’s response, but for the most part, these two are among the most commonly known.

Suggested Side Effects

There have been many suggested side effects of both short-term and long-term cannabis use. Granted, keep in mind that, like all side effects, they’re completely dependent on an individual and may not ring true for every single person. A few of the short-term effects listed in the above literature are short-term memory, altered judgment, and impaired motor functions. Some of the long-term potential effects are addiction, altering the brain’s makeup, and decreasing learning capabilities.

Marijuana and the World Anti Doping Agency (WADA)

If you compete in drug-tested strength sports, then chances are you’re well aware of WADA and its policies. This organization creates the standards for fair play rules and coordinates guidelines for athletes and banned substance use.

In the recent past, WADA actually loosened up the threshold for cannabis use pre-competition. WADA changed the threshold of positive cannabis tests from 15 nanograms per milliliter to 150ng/ml. These new limits are designed to only catch athletes who are using during competition, and testing positive at this threshold would suggest that the athlete is a fairly heavy consumer.

Previously, the rules were more strict, as marijuana in many provinces is an illegal drug. But in recent years, as marijuana continues to become more legalized and remains linked to relatively few performance-enhancing effects, it seems WADA decided to become a little more relaxed with their positive testing threshold.

Cannabis and Weight Lifting

Unfortunately, there haven’t been many studies done on cannabis and its direct effects on exercise. This is partly because the drug is still listed as an illegal substance in many states, so funding and studies become increasingly tougher to perform. However, a few studies have provided some insight into cannabis/THC’s effects on sport performance.

Cannabis and Sport Performance

Many studies have addressed that there hasn’t been enough research to claim any performance-enhancing effects cannabis may have. In fact, the few studies usually resulted in slightly decreased performance or no effect whatsoever. For example, this older study from 1986 looked at marijuana’s effects on subjects who performed maximal exercise testing to exhaustion on an ergocycle. Researchers had 12-healthy individuals split into two groups: Non-smoking, then a group that performed 10-minutes after smoking a marijuana cigarette.

Researchers found that the group who smoked marijuana cigarettes experienced a slight decrease in performance duration. The marijuana group had a cumulative performance time of 15-minute, while the non-smoking group had 16-minutes. But at peak performance, researchers found no significant differences between the VO2 (oxygen uptake), VCO2 (carbon dioxide output), heart rate, and VE (minute ventilation).

Possibly the best review published on the topic of cannabis and sports performance was released in September 2017. This review analyzed 15 studies published.

In terms of strength, one study from 1979 had six males ages 21-27 partake in a sub-maximal biking and grip strength test. They were split into two groups: THC and placebo. The authors found no effect on a subject’s grip strength, but there was a slight decrease in peak work capacity.

Another study that looked at THC and strength was performed in 1968. This study looked at 16 males aged 21-44. They performed six-10 minute bouts on the treadmill and finger ergograph (a tool to assess a muscle’s work output). The authors didn’t publish the finger ergograph’s results but noted within their study that “weakness was clearly demonstrated on the finger ergograph.”

The final study worth mentioning from the review followed 10-healthy males who were split into a control group and a THC cigarette group. Subjects performed a bicycle ergometer test that started at 150 kg/min and increased by 150 kg/min at five-minute intervals until exhaustion. Researchers recorded multiple attributes, including heart rate, VO2, VCO2, blood pressure, tidal volume, and other factors. The authors noted that the THC group all had their total work output decreased compared to the control group (who averaged 29.9-minutes), and one subject in the THC group became “stoned” and dropped out at 9.9 minutes.


Of the studies and reviews analyzed for this article, we couldn’t find one that conclusively suggested cannabis could be a performance-enhancing drug. In fact, from what we analyzed, there was a consistent slight decrease in a subject’s total work output from the use of cannabis. Yet, it’s still nearly impossible to make any definitive claims on cannabis’s impacts on strength training and sport performance for a few reasons. 

First, all of the studies were slightly older, so their methods for conducting research may differ from what researchers may currently use. Second, all of the studies had tiny populations, which could bias their results. Thirdly, none of the studies compared cannabis use with strength training programs. Fourth and lastly, none of the studies in the review looked at prolonged use of cannabis and strength training. 

In Conclusion

The use of cannabis in 41 states is still listed as illegal for recreational use. For athletes who regularly partake in tested strength sports and use marijuana regularly, they should take the WADA’s thresholds into special consideration. Due to limited research, it’s difficult to definitely say what marijuana will do to strength training and sports performance.

We hope to see more studies done on the impact of marijuana use on strength training in the future.