Cannabis and Heart Health: At a Glance
Article written by
Dipak HemrajHead of Research and Education
Content reviewed by
Dr. Lewis JasseyMedical Director - Pediatric Medicine
There is a lot of mixed evidence when it comes to cannabis, cannabinoids and heart health. Overall, it seems that marijuana use has a complicated relationship with the heart, and that its use can have both positive and negative effects on the organ.
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For this article, we are looking at three heart problems:
1. Chronic Ischemic Heart Disease (narrowed heart arteries)
2. Heart Attack
3. Heart Disease
Key Information
Total Studies = 22
Types of Study = Meta-Analysis (12); Animal Study (9); Lab Study (1)
No. of Positive Results = 13
No. of Inconclusive Results = 1
No. of Negative Results = 8
Potentially Useful Cannabis Compounds
THC (dosed carefully), CBD, myrcene, beta-caryophyllene
Positives
- Cannabinoids like CBD may help protect the heart from further damage – medical cannabis could be “cardioprotective”
- Medical cannabis may help treat other problems associated with heart diseases, such as obesity and diabetes
- For those who cannot tolerate blood-thinning medications such as warfarin or aspirin, CBD may be an alternative
Negatives
- Smoking cannabis may increase the chances of heart attack or stroke in some people, especially younger people aged under 45
- Cannabis may not be ideal for those suffering from irregular heartbeat (arrhythmia)
- No clinical trials on medical cannabis for the treatment of different kinds of heart problems
Possible Efficacy
Low to moderate
Medical Cannabis and Heart Problems: a Complicated Story
The evidence on whether medical cannabis can help treat heart problems is a complex one. There are many studies showing that medical cannabis can help, others showing far more negative effects. There is a lot of debate on whether cannabis can increase or decrease blood pressure and hypertension, with the consensus so far saying that using cannabis can increase blood pressure in the short term, but decrease it in the long-term. This may be one reason why there are so many mixed results when it comes to strokes.
So, why is this the case? Well, there are several variables to consider when looking at cannabis in relation to heart health. These include:
- What other health problems does the person with heart issues have?
- How old is the patient?
- How active is the patient, and what is their diet like?
- What ingestion method/s are they using?
All of these factors may influence whether or not cannabis is useful for heart problems.
What is Chronic Ischemic Heart Disease, and How Does Cannabis Help?
Chronic ischemic heart disease is the term given to heart problems caused by narrowed heart arteries, which means less blood and oxygen getting into the heart. This can cause chest pain (angina) and heart attacks.
There are 5 studies on medical cannabis for chronic ischemic heart disease (4 animal and 1 meta-analysis). All studies show positive results, although it must be said that these are mostly studies on animals.
As for the reasons why medical cannabis seems to help with ischemic heart disease, it seems that cannabinoids play a protective role, in a similar way to how cannabinoids may protect against traumatic brain injuries (TBIs).
- One study suggests that “A single ultra low dose of THC before ischemia is a safe and effective treatment that reduces myocardial ischemic damage.”
- Contrary to the above, this study shows that a low dose of THC increases blood pressure, whereas higher doses decrease
- The terpene beta-myrcene “protects oxidative and histological damage in the heart tissue after global ischemia-reperfusion and may be [a] useful safe alternative treatment for cardiac tissue after ischemic stroke.”
- CBD may help reduce inflammation associated with ischemic heart disease.
What Are Heart Attacks and How Might Cannabis Help?
A heart attack is a very serious condition where the supply of blood to the heart is suddenly blocked. Symptoms of a heart attack include chest pain, shortness of breath, dizziness and sweating. They are a very common cause of death in the US and the world over – cardiovascular diseases (CVDs) cause an estimated 17 million deaths per year worldwide. Heart attacks are sometimes called a “myocardial infarction.”
When it comes to heart attacks, there is a lot of debate around how medical cannabis could be useful. It is suggested that, with THC use in particular, the immediate heart rate and blood pressure increasing effects may increase the chances of a heart attack occurring in adults under 45 years-old. These effects seem to be more pronounced when smoking cannabis.
On the other hand, some studies show that “amongst older adults with hypertension, cannabis treatment for 3 months was associated with a reduction in 24-hours systolic and diastolic blood pressure values with a nadir at 3 hours after cannabis administration.” This could be due in part to cannabinoids’ anti-inflammatory properties, as well as its ability to reduce stress & anxiety, regulate blood-glucose levels, and the vasodilatory (artery opening) effects of THC, CBD and pinene.
High flavonoid intake may also decrease the risk of cardiovascular disease due to their antioxidant properties. Cannabis is full of flavonoids, with cannflavins showing promise as an anti-inflammatory that’s 30 times more powerful than aspirin.
A look at the studies on the relationship between cannabis use and heart attacks shows both positive and negative results in almost equal measure. There are:
- 19 studies overall
- 10 studies show that medical cannabis may be useful for treating heart attacks
- 8 studies are negative
- 1 study is inconclusive
It should be said that some of the studies showing the positive effects of cannabis were on patients after they suffered a heart attack, whereas any of the negative findings were found with younger people who smoked cannabis about an hour before their heart attack.
The ingestion method matters, as those who ingested cannabis did not suffer from these effects to the same degree. Age also seems to matter, and older patients with hypertension may benefit more than younger patients. The other factor is the amount of THC ingested, with some showing a cardioprotective effect at lower doses, but others showing an increase in blood pressure in low doses (decrease in higher doses).
Overall, the jury’s still out, and many more studies are needed to prove or disprove any definitive link between cannabis use and heart attacks.
What is Heart Disease and How Does Cannabis Help?
Heart disease is an umbrella term used for many different kinds of problems, including cardiovascular diseases (CVDs) and conditions that affect your heart’s muscle, valves or cause abnormal rhythms (arrhythmias). Heart diseases are the number one cause of death in the US, with one person dying every 36 seconds from a CVD. Between 2016 and 2017, heart disease cost about $363 billion when taking into account the cost of healthcare services, medicines and loss of productivity.
Medical cannabis and cannabinoids may help reduce inflammation and blood/heart rate when dosed appropriately, but there are some other, less direct ways medical cannabis may help treat heart diseases. These include:
- Helping treat stress, anxiety, insomnia and depression, all of which increase the likelihood of suffering from a heart disease
- Helping treat metabolic syndrome (increased blood pressure, high blood sugar, excess body fat around the waist, and abnormal cholesterol or triglyceride levels): “Among emerging adults, current marijuana users were 54% less likely than never users to present with metabolic syndrome.”
How Are Heart Diseases Currently Treated?
When it comes to heart disease, prevention is certainly better than cure. The most common treatment is a change in lifestyle – eating less salt and refined sugar, limiting or quitting alcohol intake, stopping smoking (ingesting cannabis may be a better alternative for the heart-healthy effects), and getting moderate-intensity exercise on most days of the week.
Should lifestyle changes not work, medications may be prescribed. Common medications include:
- Blood thinners like warfarin to ease blood flow
- Antiplatelet agents like aspirin or clopidogrel to stop blood sticking together
- Angiotensin-converting enzyme (ACE) inhibitors like benazepril (Lotensin) to expand blood vessels
- Angiotensin II receptor blockers (or Inhibitors) like azilsartan (Edarbi), which help prevent the chemical – angiotensin II – from having any effect on the heart or blood vessels
- Angiotensin receptor-neprilysin inhibitors (ARNIs) like neprilysin or sacubitril/valsartan (Entresto), opening narrow arteries
- Beta blockers like acebutolol, which decreases the heart rate and force of contraction, lowering blood pressure
- Cholesterol-lowering medications like statins, which interrupt the development of cholesterol in the blood
Whilst many of these medications are generally very well-tolerated, in some instances they can cause severe side-effects. Statin therapy, for example, may cause muscle pain and damage, liver damage, nerve pain and other neurological damage, and an increased chance of type-2 diabetes. Cannabinoids like CBD certainly present a less-dangerous alternative.
Useful Cannabinoids and Terpenes
- Tetrahydrocannabinol (THC) may be useful, but more information is needed on dosage
- Cannabidiol (CBD) may be useful in reducing inflammation, anxiety and improving blood flow
- Myrcene’s antioxidant properties may help protect against heart disease
- Beta-caryophyllene may also have cardioprotective effects
Free Cannabinoid and Terpene Guide
Cannabis and the Heart: Overall
As with most other conditions, we need more studies (in particular clinical trials) to see how, why and when medical cannabis and cannabinoids may help treat different types of heart disease. At the moment, the evidence for cannabis’ efficacy is mixed, and there may be some heart conditions where cannabis may help and others where it may hinder cardiovascular health. Age, activity levels and ingestion method also makes a big difference, so these factors should be taken into account.
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