What Cannabis Does to Your Heart and Blood Vessels
Cannabis increases heart rate and can cause blood pressure drops when standing, with tolerance developing rapidly to most cardiovascular effects, but poses risks for people with existing heart disease.
Quick Facts
What This Study Found
Cannabis and THC increased heart rate, slightly increased blood pressure when lying down, and occasionally caused marked drops in blood pressure upon standing. Cardiac output increased while peripheral vascular resistance and maximum exercise performance decreased. Tolerance to most cardiovascular effects developed rapidly with repeated use.
With continued exposure, blood pressure while lying down decreased slightly, standing blood pressure drops disappeared, blood volume increased, and heart rate slowed. These changes were consistent with reduced sympathetic and enhanced parasympathetic nervous system activity. For most young, healthy users, these effects were not associated with serious health problems. However, occasional myocardial infarction, stroke, and other adverse cardiovascular events had been reported, and smoking cannabis posed particular risks for people with existing cardiovascular disease due to increased cardiac workload, catecholamine levels, and carbon monoxide exposure.
Key Numbers
No specific numerical data were presented in the abstract, though the review described characteristic patterns of heart rate increase and blood pressure changes.
How They Did This
This was a narrative review of the cardiovascular pharmacology of cannabis, covering human and animal studies of acute and chronic effects, tolerance development, and clinical safety considerations. It addressed both receptor-mediated and endocannabinoid system mechanisms.
Why This Research Matters
This review provided a comprehensive account of how cannabis affects the cardiovascular system, distinguishing between effects in healthy young users (generally benign) and risks in people with heart disease (potentially dangerous). The description of rapid tolerance development to cardiovascular effects was clinically relevant for understanding both recreational and medical cannabis use.
The Bigger Picture
Subsequent research has confirmed and extended these findings. Large epidemiological studies have found that cannabis use may increase the risk of heart attack and stroke, particularly in older users and those with cardiovascular risk factors. The recognition of cardiovascular risks has become more prominent as cannabis use has expanded to older populations through legalization.
What This Study Doesn't Tell Us
As a narrative review, the evidence was synthesized without systematic methodology. Most data came from studies in young, healthy subjects and may not apply to older or medically compromised populations. The mechanisms of rare but serious cardiovascular events were not fully elucidated.
Questions This Raises
- ?How does the cardiovascular risk of cannabis compare to that of tobacco or alcohol?
- ?Do non-smoked routes of cannabis administration reduce cardiovascular risks?
- ?Should people with heart disease be specifically warned against cannabis use?
Trust & Context
- Key Stat:
- Cardiovascular tolerance develops rapidly; risks mainly for those with heart disease
- Evidence Grade:
- This is a comprehensive narrative review by an established pharmacologist, providing moderate-level evidence through synthesis of clinical and preclinical data.
- Study Age:
- Published in 2002. Subsequent large studies have provided more data on cardiovascular risks, particularly in older populations.
- Original Title:
- Cardiovascular system effects of marijuana.
- Published In:
- Journal of clinical pharmacology, 42(S1), 58S-63S (2002)
- Authors:
- Jones, Reese T
- Database ID:
- RTHC-00122
Evidence Hierarchy
Summarizes existing research on a topic.
What do these levels mean? →Frequently Asked Questions
Can cannabis cause a heart attack?
Rare cases of heart attack after cannabis use have been reported, primarily in people with existing cardiovascular disease. For young, healthy users, the cardiovascular effects were generally not associated with serious problems in this review.
Does your body get used to the heart effects of cannabis?
Yes. This review found that tolerance to most cardiovascular effects of cannabis developed rapidly with repeated use. Heart rate increases diminished, blood pressure drops when standing disappeared, and heart rate actually slowed with chronic use.
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Cite This Study
https://rethinkthc.com/research/RTHC-00122APA
Jones, Reese T. (2002). Cardiovascular system effects of marijuana.. Journal of clinical pharmacology, 42(S1), 58S-63S.
MLA
Jones, Reese T. "Cardiovascular system effects of marijuana.." Journal of clinical pharmacology, 2002.
RethinkTHC
RethinkTHC Research Database. "Cardiovascular system effects of marijuana." RTHC-00122. Retrieved from https://rethinkthc.com/research/jones-2002-cardiovascular-system-effects-of
Access the Original Study
Study data sourced from PubMed, a service of the U.S. National Library of Medicine, National Institutes of Health.
This study breakdown was produced by the RethinkTHC research team. We analyze and report published research findings without making health recommendations. All interpretations are based solely on the published abstract and study data.