Cannabis use and blood pressure: How are they linked?
The following is a part of a series on blood pressure writings commissioned by Hilo, a creator of blood pressure wristbands.
Using cannabis has become increasingly common in Canada, but how does it interact with the heart and circulatory system?
Cannabis, commonly referred to as ‘weed’ or ‘marijuana’, has been used in Canada for medical purposes since 2001 due to having some anti-inflammatory properties. It was then legalised for recreational use in 2018.
However, its effects on the body vary, and are still subject of numerous pieces of research.
Canadian legalisation
The drug was greenlit for recreational use in October 2018 under the Cannabis Act, making Canada the first major industrialised country to go through with legalisation.
The Canadian government, led by then-Prime Minister Justin Trudeau, argued that legalising the drug would do more to restrict young people from purchasing cannabis, hurt criminal organisations, and ensure quality control on the substance.
After the legislation was passed Canadians gradually started buying cannabis through the official channels, mainly due to the safety and convenience of doing so. By 2023 the proportion of Canadians buying cannabis legally rose to 73%, up from 37% in 2019.
While legalisation made the drug more visible, with the help of high street stores and destigmitisation, cannabis use was rising even before it was legalised. Before 2018 people were either buying from street dealers or ‘grey market’ stores, which started popping up in the 2010s, particularly in British Columbia.
Worldwide adoption
The use of cannabis has also increased outside of Canada, with an estimated 244 million users in 2025, up from around 178 million people aged 15 to 64 years who used cannabis at least once in 2012.
The Netherlands decriminalised the drug in 1976, while Uruguay legalised the drug in 2013, signalling a lighter touch approach in parts of the world. Today notable exceptions are in parts of the Middle East and Asia, notably Singapore and Saudi Arabia, where smuggling the drug into the country could land you with life imprisonment or even the death penalty.
Medical use
Cannabis is only legal for 'medical purposes’ in some countries or locations. In the United States 40 of the 50 states have greenlit the drug for medical purposes, though only 24 of the states officially allow the drug to be used recreationally.
‘Medical cannabis’ usually means the use of cannabis or cannabinoids (chemicals derived from cannabis plants) as medical therapies, for example to treat disease or alleviate symptoms. These can be administered orally, sublingually (under the tongue), or topically; as well as being smoked, inhaled, mixed with food, or made into tea.
Since the drug was legalised in Canada, a number of older adults have become new users. For this demographic it’s often associated with medical use, for example pain management. But there is a flip-side: it was also observed that those users were unlikely to receive guidance from healthcare professionals, often relying on other non-clinical sources, and healthcare professionals and researchers alike have flagged the significant risk of knowledge gaps developing.
Medical cannabis study
A study that considered data from randomised clinical trials on cannabinoids for a range of medical conditions said there was moderate evidence to support their use for treatment of chronic pain and muscle spasticity.
They also noted low-quality evidence that cannabinoids were associated with improvements in nausea and vomiting due to chemotherapy, weight gain in HIV, sleep disorders, and tourette syndrome.
However, there was a downside, as the use of these cannabinoids was associated with short-term adverse effects (AEs) such as dizziness, confusion, diarrhoea and drowsiness.
Cannabis: What we know
Cannabis contains two chemical substances that impact on the human body: Δ‐9‐tetrahydrocannabinol (also known as THC), and cannabidiol (CBD). These chemical entities are closely related in terms of chemical structure, but have different effects.
THC: The primary psychoactive component of cannabis and responsible for the typical ‘high’. It interacts with both cannabinoid receptor 1 (CB1R) and cannabinoid receptor 2 (CB2R). CB1Rs are located in the brain, heart, liver, cardiovascular system, skin and muscles whereas CB2Rs are in the gastrointestinal tract and leukocytes/immune cells.
CBD: Can interact with the body’s cannabinoid receptors, and can have antioxidant and anti-inflammatory effects as a result. However, the actions on the body are complex, and still being uncovered. Ottawa Heart Health recommended for people to use low THC and high CBD products, signalling that the former is seen as more problematic for heart health.
When it comes to the impact of cannabis use on the cardiovascular system, there have been very few studies. These are often small-scale, short-term, or suffering from several limitations.
There are several methods for taking cannabis such as smoking, vaporising, ingestion or topical application (directly onto the skin). Each of these different ways of administration will affect how much of the active ingredients you’re exposed to and, potentially, how they interact with your body.
Cannabis use and the biological effects
The biological effects of cannabis on the body can vary between individuals, and may depend upon how they consume it. For example, if cannabis is inhaled into the lungs, the active compounds will enter your bloodstream rapidly, quickly reaching your brain and other organs, taking effect within a few seconds to a few minutes.
However, eating or drinking cannabis-containing products requires your body to digest the materials, leading to a slower-onset.
In Canada the way people consume cannabis has become varied, with some people switching to edibles and vaping. 2023 research shows that smoking is only narrowly the most common method of consuming cannabis (63%) in Canada, followed by eating (52%) and vapourizing with a vape pen or e-cigarette (33%).
Across Canada edibles are commonly sold in the form of gummies, chocolates, baked goods, and beverages.
Smoking cannabis
Some research links the act of smoking the drug with cardiovascular issues, as a 1998 study associated frequent cannabis smoking with significant airway inflammation similar in frequency, type, and magnitude to the lungs of tobacco smokers.
Like smoking tobacco, cannabis smoking exposes the body to carcinogens and toxins, such as carbon monoxide, which effectively reduces the amount of oxygen the heart gets.
A 2017 journal associated cannabis smoking with a 20% to 100% increase in heart rate lasting 2-3 hours, as well as acute coronary events. Meanwhile a 2024 study recommended avoiding smoking cannabis to reduce their risk of premature cardiovascular disease and cardiac events.
Given these apparent risks, Ottawa Heart Health recommends avoiding smoking or vaping cannabis, instead recommending edibles, oils or capsules.
That being said, some research plays down the carcinogenic effects of smoking cannabis, as a 2005 paper found that smoking cannabis is less likely to cause lung cancer than with tobacco.
Overdosing
While overdosing on cannabis is rarely fatal, it can have unpleasant physical and psychological effects.
Taking too much cannabis can lead to elevated heart rate and a drop in blood pressure, potentially causing cardiovascular damage. It can also elevate issues with poor mental health, causing paranoid, hallucinations, anxiety and/or panic attacks. Other symptoms of cannabis poisoning can include chest pain, nausea/vomiting, psychotic episodes and difficulties breathing.
While edibles are sometimes seen as healthier than smoking, the delayed effects of consuming cannabis orally can leave the user more at risk of taking too much - as it takes 30 minutes to two hours for the effect to kick in.
Subsequently the Canadian Centre on Substance Abuse and Addiction provides a fact sheet - reproduced by the British Columbian provincial government - which recommends people to ‘start low - go slow’, especially as some effects can last up to 24 hours. If the effects are unpleasant people can be stuck with them for a long time.
Cannabis and heart health
The University of Ottawa Heart Institute warns that cannabis use initially causes blood pressure to drop before it later rises, which puts a strain on the heart - leaving you more at risk of a heart attack. Therefore the main issue is cannabis use leads to less stable blood pressure levels, rather than causing an increase. The institute quoted a study funded by the National Heart, Lung, and Blood Institute, which concluded that daily cannabis use increases the risk of a heart attack by 25%, and a stroke by 42%, compared to non use.
A US-based study also looked at the association between cannabis use and cardiovascular outcomes among the general population, never‐tobacco smokers, and younger individuals (aged 18 to 74 years old). While this was not a trial and relied upon pre-collected data (leading to some study limitations), the use of cannabis was associated with increased risk of myocardial infarction (heart attack) and stroke, with a higher risk seen when the participant used cannabis more regularly, independently of whether they smoked regular tobacco cigarettes. In fact, another study that investigated the link between recreational substance use among adults showed its link to premature atherosclerotic cardiovascular diseases (ASCVD), regardless of which substance was taken.
So far, it seems that the connection between cannabis use and poorer heart health is clear-cut, but there is one conflicting study, where the researchers showed that among older adults (average age 70.42) with hypertension, cannabis treatment for three months was associated with a reduction in systolic and diastolic blood pressure values, with the biggest drop three hours after cannabis administration. However, this study has some severe limitations, which should be taken into account: it was small-scale, there was no control group, some patients were already taking blood pressure medications, and most participants had pre-existing underlying health conditions that could impact upon their blood pressure, such as diabetes.
THC and its effects
The impact of cannabis on the body depends upon the THC content, with higher THC content leading to a more intense effect. When it comes to the adverse cardiovascular effect of cannabis, it’s the THC level that we need to consider.
A clinical trial published in the Journal of the American Heart Association in 2024 looked into the impact of THC on the cardiovascular system. The trial found that in THC-dominant cannabis, regardless of mode of inhalation (smoking or vaporising) participants experienced: An increase in heart rate, and an increase in BP.
Both of these effects were suspected to increase arterial stiffness and reduce diastolic function of the heart (the heart's ability to relax and fill the ventricles with blood between beats).
CBD and its benefits
You may have heard of CBD-based products that are marketed as having health benefits, including general well-being, relaxation, stress and pain relief. Indeed, when studies talk of the adverse effects of cannabis on the cardiovascular system, it is mainly due to the THC component.
Cannabidiol, or CBD, is a major component within cannabis that does not lead to the ‘high’ associated with THC, even though both compounds are similar structurally. However, it does have some physiological impacts, and has been shown to lead to anxiolytic effects – such as a reduction of anxiety, panic, and tension.
A Brazil study showed that a single dose of CBD prior to subjecting a participant to something that scared them reduced anxiety, cognitive impairment and discomfort. However, the researchers stated that more clinical trials on larger cohorts were needed. When it comes to CBD and BP, another study from Brazil published in 2025 suggested that long-term use of CBD may be useful for BP control in hypertensive patients due to its vasorelaxant properties, but further investigation is required.
Mental health
A number of studies have made a connection between cannabis use and poor mental health, as the Government of Canada warned that daily or near-daily use of cannabis increases the chance of developing disorders related to anxiety and depression.
Regularly consuming cannabis is also seen as a significant risk factor for schizophrenia, particularly in young men, as well as paranoia, hallucinations and panic attacks.
From a blood pressure standpoint this is concerning, as poor mental health is linked with abnormal blood pressure. Anxiety can cause temporary spikes in blood pressure, while hypertension is associated with poorer mental health years before a diagnosis is ever made.
Poor mental health can lead to unhealthy coping measures which contribute to high blood pressure, such as drinking too much alcohol, having a poor diet, and not doing enough exercise.
Cannabis and young people
Cannabis use is shown to affect brain development in young people, impairing memory, learning attention and executive brain function, and heightening mental health risks.
A 2026 research paper which used multiple studies between 2013 and 2025 estimated that the odds of depression were 51% higher in cannabis users between 15 and 30. Anxiety was present in 58% more cases, while most alarmingly suicide attempts had 80-87% higher odds.
However, whether cannabis use is conclusively to blame for poor mental health is unclear, as people struggling with depression and anxiety may use cannabis as a form of self-medication. While there seems to be a connection, it’s uncertain if there’s causality between cannabis use and depression, anxiety, suicidal thoughts and suicide attempts.
Why synthetic cannabis should be avoided
While there’s some conflicting research regarding how harmful cannabis consumption can be, if you are going to consume the drug you should buy it legally - where it’s regulated and you know what goes into it.
As the Government of Canada warns, illegal cannabis is not tested or quality controlled and may contain harmful levels of contaminants, including heavy metals, pesticides, mould, cutting agents, or bacteria. Levels of THC and CBD are also controlled with legal cannabis, so there’s less chance of the user taking too much.
Synthetic products like ‘K2’ and ‘spice’ - which mimic the effects of THC - should also be avoided because they pose a far greater risk to the user than the natural plant. The likes of K2 are said to be 10 to 100 times stronger than natural cannabis, which can lead to adverse reactions like heart attacks. They can also be laced with toxic substances, like rat poison (brodifacoum), which is commonly added as it elicits euphoria.
The take-home
While there is much hype around the use of cannabis as a medical treatment, with some evidence for its clinical effect in certain use-cases, such as treatment of chronic pain and muscle spasticity, its broader benefits are still being debated. For instance, US-based researchers are warning of an increased risk of heart attacks and strokes, especially in those with pre-existing cardiovascular disease.
Proven natural methods for lowering blood pressure instead of cannabis
While the use of cannabis to lower BP is unproven, there are other ways that you can look at to reduce your blood pressure and help your heart health naturally. Regular exercise, a balanced diet with less salt and more vegetables, targeted stress reduction, sufficient sleep, and abstaining from smoking and alcohol are strong foundations for your heart health journey.
This is where the Hilo Band comes in: with continuous, cuffless blood pressure monitoring round the clock, you can keep track of your readings – without disruptive measurements in your daily life. Hilo analyses the data, recognises patterns, and provides valuable insights that help you and your doctors make informed decisions. This makes the treatment of high blood pressure more precise and effective, and gives you the peace of mind that you're doing the best for your health. In fact, we’ve upgraded the app, so the Hilo Band can now monitor your step count and sleep data, allowing you to quickly see the benefits of increasing your physical activity or achieving high-quality sleep.
FAQ
Is cannabis good for high blood pressure? Cannabis is not a proven therapy for high blood pressure. US-based trials have shown that consumption of THC-dominant cannabis led to an increase in heart rate, and an increase in BP. These outcomes were suspected to increase arterial stiffness and reduce diastolic function of the heart. While CBD, another component of cannabis, may be useful for BP control with long-term use in hypertensive patients due to its vasorelaxant properties, further investigation is required.
What can I do to reduce my blood pressure? In the short term, rest, deep breathing (box breathing), and stress reduction are helpful methods for reducing blood pressure. Longer term, regular exercise, a healthy diet, a reduction in salt (sodium) intake, and medication (if necessary) are most effective. Continuous blood pressure monitoring with the Hilo Band makes it possible to recognize your BP patterns and see the impact of any interventions quickly and easily.
Is cannabis good for the heart? In short, no. Exposure to THC can increase your heart rate and raise your risk of heart attacks, especially in people with pre-existing heart conditions. Studies have shown that CBD has protective and vasodilating effects, but large-scale long-term studies are lacking. Caution is advised.
The information in this article is intended for educational purposes only and does not replace medical advice. If you suspect hypertension or are worried about your blood pressure, speak to your doctor. They can advise on the best way to effectively manage it. If you believe that you, or a loved one, needs any additional advice or support in relation to drug use or addiction, resources are available including Canadian Treatment Addiction Centres (CATC).
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