The use of cannabis, colloquially known as being “high,” before or during physical activity is a growing practice, particularly where it is legally available. This trend raises important questions about how the active compounds in cannabis interact with the physiological demands of exercise. Understanding the true effects on the body, in terms of both safety and athletic performance, requires scientific inquiry. The intersection of cannabis use and working out is complex, involving potential risks due to immediate impairment and nuanced effects on endurance and recovery. This discussion examines the acute dangers, measurable performance changes, and the underlying biological mechanisms at play.
Immediate Physical Safety Concerns
The most pressing issue when combining cannabis and exercise involves acute impairment, which significantly elevates the risk of injury. Tetrahydrocannabinol (THC), the primary psychoactive component in cannabis, alters motor control and coordination. This impairment leads to slower reaction times and reduced accuracy, making complex movements, such as weightlifting or cycling, more hazardous. THC acts on brain regions involved in motor control, resulting in decreased fine motor skills and impaired balance.
Cardiovascular strain is a serious consideration, as THC acutely increases heart rate and elevates blood pressure. When combined with the natural increase in cardiac work from moderate-to-vigorous exercise, the heart is subjected to greater stress. Individuals with pre-existing cardiovascular conditions face a particularly high risk. Reports show an increased risk for heart attack or stroke immediately following cannabis use, which is compounded by the physical demands of a workout.
Cannabis use can also compromise a person’s perception and judgment during physical activity. Users may experience an altered perception of effort, sometimes feeling the workout is easier or more enjoyable, which can be deceiving. This impaired judgment may cause a person to ignore signs of fatigue or pain, leading to overexertion, poor form, or pushing through an injury that requires rest.
Performance and Endurance Impact
The effects of cannabis on objective athletic performance are generally negative or neutral, despite some users reporting a subjective boost in enjoyment. Studies measuring direct performance metrics, such as a 20-minute cycling time trial, show that consuming THC-containing cannabis significantly reduces mean power output. While maximal heart rate may be similar to sober conditions at maximum effort, the elevated heart rate during submaximal exercise indicates a less efficient cardiovascular response.
The impact on aerobic capacity, often measured by VO2 max, generally leans toward a detrimental effect on endurance performance. THC consumption increases the subjective feeling of effort, meaning the same intensity of exercise feels significantly harder to the user. This altered perception of effort, even if objective performance metrics remain unchanged, contributes to a less effective training session.
For strength and power output, existing data does not support an ergogenic, or performance-enhancing, effect from THC. The psychotropic effects of THC, including reduced motivation or slower reaction times, are likely to hinder movements requiring precision and explosive power. In contrast to the acute effects of THC, Cannabidiol (CBD) is being investigated for its potential role in post-exercise recovery. CBD may aid recovery by improving sleep quality and reducing inflammation, but this is distinct from the immediate performance effects of being high during the workout.
How Cannabis Compounds Interact with Exercise
The effects of cannabis on the body during exercise are rooted in its interaction with the endocannabinoid system (ECS), a complex signaling network that helps maintain homeostasis. The body naturally produces endocannabinoids, such as anandamide, which bind to the CB1 and CB2 receptors and contribute to the euphoric feeling known as the “runner’s high.” Exogenous cannabinoids, like those found in the cannabis plant, introduce outside compounds that bind to these same receptors, overriding the body’s natural system.
The two most abundant compounds, THC and CBD, interact with the ECS differently, resulting in varied effects. THC is psychoactive because it binds directly to the CB1 receptors, which are highly concentrated in the brain and nervous system, leading to cognitive and motor impairments. CBD does not bind directly to these receptors with high affinity but instead modulates the ECS indirectly, often dampening the psychoactive effects of THC. CBD’s primary effect is thought to be through its anti-inflammatory and pain-modulating properties, making it relevant for recovery.
The ability of cannabis to mask pain is a double-edged sword in the context of exercise. While the analgesic effects reduce the sensation of discomfort, they do not address the underlying physical issue. This pain masking can lead to a greater risk of overuse or traumatic injuries because the body’s natural warning signals are suppressed. Furthermore, the activation of the CB1 receptors by THC may interfere with physiological pathways governing motivation and muscle signaling, contributing to the decline in objective performance metrics.