Marijuana use among older adults is associated with a heightened risk of atrial and ventricular arrhythmias, according to new research published in the American Journal of Cardiology.[1]

“Marijuana is widely used across the United States, and marijuana use has increased from 2.4% in 2015 to 4.2% in 2018 among adults aged ≥65 years,” wrote first author Barbara N. Harding, PhD, with the Barcelona Institute of Global Health, and colleagues. “Marijuana use increases sympathetic nervous system activity and inhibits cardiac parasympathetic innervation, resulting in elevated heart rate, elevated blood pressure, and an increase in myocardial oxygen demand.”

Harding et al. tracked data from the Multi-Ethnic Study of Atherosclerosis (MESA), focusing on data from nearly 1,500 participants. All participants were between the ages of 45 and 84 years old and free of cardiovascular disease when they first enrolled in MESA from 2000 to 2002. After enrollment, follow-up examinations occurred every two to six years. Each individual underwent at least 24 hours of extended electrocardiographic (ECG) monitoring.

Each patient was asked several questions about marijuana use after their sixth examination. They also reported other key details about their lifestyle.

Ten percent of study participants reported prior marijuana use. While 28.5% of participants were current users, 50.7% reported prior use. The remaining participants did not specify the timing of their marijuana use.

Marijuana users, whether they were still using it or had done so in the past, tended to be younger than individuals who had never used marijuana. They were also more likely to be men and/or have a history of smoking cigarettes.