Physical Performance Impairment with Cannabis Consumption in Adults Over 12 Hours.

Assessing cannabis-induced impairment in physical performance is critical for safety-sensitive occupations. This study evaluated the magnitude and duration of impairment following acute cannabis use. Twenty-eight adult users completed baseline and follow-up assessments at 1, 6, and 12 h after smoking a standardized cannabis cigarette. Measures included subjective intoxication, vital signs, psychomotor performance, muscle strength, balance, and endurance. Blood Δ9-tetrahydrocannabinol (THC) concentrations peaked at one hour and declined by six hours (p < 0.001), while Carboxy-THC showed minimal temporal variation (p = 0.005). Cannabis use significantly increased systolic blood pressure and heart rate, elevated muscle force variability, reduced the rate of force development, and impaired balance and endurance for up to 12 h. Despite reduced perceived intoxication, measurable functional impairments persisted, indicating prolonged performance effects.