Delta-8 THC is a psychoactive cannabinoid that is chemically similar to delta-9 THC, the primary psychoactive compound in cannabis. Delta-8 has become increasingly popular over the past couple years as a legal alternative to delta-9 in states where cannabis is not fully legalized. One of the concerns around delta-8 is whether it can increase heart rate like delta-9 THC and whether this poses any cardiovascular risks.
What is delta-8 THC?
Delta-8 THC or delta-8 tetrahydrocannabinol is one of over 100 cannabinoids produced naturally by the cannabis plant. It is an isomer of delta-9 THC, meaning it has a similar chemical structure but some differences in the arrangement of its atoms.
Delta-8 occurs in very small concentrations in most cannabis strains, usually less than 1% of the total THC. Recently, extraction and conversion processes have been developed to isolate and concentrate delta-8 from hemp, which naturally contains higher levels of its precursor CBD. This has allowed delta-8 products to be produced legally from hemp and sold in many places where recreational cannabis is still prohibited.
Delta-8 is considered a psychoactive substance, capable of producing a mild “high” similar to but less potent than delta-9 THC. Some of the reported effects include euphoria, relaxation, increased appetite, and mitigation of nausea and pain.
How delta-8 affects the body
Like delta-9 THC, delta-8 THC exerts its effects in the body by interacting with the endocannabinoid system, specifically binding to the CB1 receptors in the brain and nervous system. This stimulation of CB1 receptors is responsible for the mood-altering and perceptual effects associated with being “high.”
In addition to the central nervous system effects, delta-8 is believed to impact the cardiovascular system. Many cannabinoids, including THC, have complex effects on heart rate, blood pressure, and other cardiovascular functions.
Increase in heart rate
One of the primary effects of THC, both delta-8 and delta-9, is an increase in heart rate, also known as tachycardia. This happens acutely right after ingesting or inhaling THC when the user feels high. The accelerated heart rate can persist for 1-3 hours.
Research on the effects of cannabis indicates that inhaled THC causes an abrupt increase in heart rate that peaks at 15-30 minutes. Orally ingested THC also causes a rise in heart rate but the onset is delayed and peak effects occur at 90-120 minutes as the body metabolizes the THC in the digestive tract.
In a benchmark 1990 study, heart rate increased by an average of 16 beats per minute after smoking THC compared to only 3 bpm after smoking placebo cannabis with the THC removed. Other studies have consistently shown THC from cannabis can boost heart rate anywhere from 20-50 bpm above baseline depending on dose, method of ingestion, and tolerance level of the user.
Increase in blood pressure
Along with faster heart rate, THC from cannabis also triggers a temporary spike in blood pressure in most users immediately after ingestion. However, the duration and magnitude of the blood pressure response varies considerably across studies.
Data on the acute impact of THC on blood pressure come mainly from measurements taken while participants were lying down. In this posture, systolic blood pressure (top number) increased by an average of 10-15 mm Hg and diastolic blood pressure (bottom number) by 5-10 mm Hg lasting anywhere from 2-3 hours. The rise in blood pressure tends to track closely with the elevation in heart rate.
Less research has examined blood pressure changes after standing up, which normally causes a transient increase known as postural hypotension. A few studies in the 1970s and 80s found postural hypotension was significantly greater after cannabis inhalation, suggesting THC may impair the body’s mechanisms to adjust blood pressure in response to postural change.
Mechanisms for cardiovascular effects
The mechanisms behind the cardiac and circulatory effects of cannabinoids like THC are complex and not fully elucidated. Several pathways may be involved:
- Sympathetic stimulation – THC activates the sympathetic nervous system, part of the fight-or-flight response, leading to increased heart rate and contracted blood vessels.
- Reduced parasympathetic tone – THC may inhibit parasympathetic activity, decreasing the relaxation response and cardiac control.
- Increased cardiac output – THC can directly influence heart function to elevate cardiac output.
- Reduced vascular resistance – THC causes blood vessels to dilate, which can lower blood pressure. This can counteract the blood pressure-raising effect of increased cardiac output.
The interplay of these systems determines the cardiovascular effects experienced after consuming cannabis. Dose, tolerance, administration method, and a user’s own physiology help shape individual response.
Short-term cardiac risks
For healthy individuals without cardiovascular disease, the heart-racing effect of delta-8 THC is unlikely to pose serious risks in the short term. But it can produce unpleasant sensations.
The increase in heart rate may be perceived as palpitations or a pounding heart. Delta-8 could exacerbate chest pain symptoms in someone with undiagnosed heart disease. It can also trigger anxiety or panic attacks in susceptible users due to physical symptoms like a racing, skipped, or irregular heartbeat.
In individuals with diagnosed heart conditions, delta-8 THC could present higher risks by causing tachycardia, elevated blood pressure, or increased demand on the heart. Those with arrhythmias, hypertension, recent myocardial infarction, or heart failure may need to exercise greater caution with delta-8 use.
No deaths directly attributed to delta-8
There are no documented reports of fatal overdoses or deaths definitively caused by delta-8 THC itself. Unlike opioids which suppress respiratory function at high doses, THC is not associated with lethal effects from toxic levels in the body.
However, adverse cardiovascular events could be triggered in people with preexisting heart disease using potent THC products. Older case reports have linked heavy cannabis use to heart attacks and strokes, but determining causality is difficult.
Long-term cardiovascular effects
Many of the studies examining THC and cardiovascular effects focus on acute changes observed after minutes and hours. Less research has evaluated the long-term cardiovascular consequences of prolonged cannabinoid exposure.
Some studies suggest the tachycardia and increased cardiac demand stimulated by THC could promote adverse remodeling and impaired function over time. But data is mixed and confounded by lifestyle factors.
One study followed nearly 2000 participants over 25 years. Cumulative cannabis use was associated with higher diastolic blood pressure and obesity but not greater incidence of cardiovascular disease.
In contrast, a large retrospective study found marijuana users had a 3.2 times higher risk of dying from hypertension compared to non-users and 3 times greater risk of cerebrovascular deaths.
Overall, heavy cannabis use may potentially escalate risk for hypertension, arrhythmias, stroke, and other cardiovascular diseases. But larger, controlled studies are needed to clarify if THC exerts cumulative damage versus simply reflecting other confounding variables.
Popularity of delta-8 THC
The delta-8 THC market has absolutely exploded since early 2019. There are now thousands of online vendors selling delta-8 products, touting its legal advantages and promoting perceived benefits over delta-9 THC.
This rapid growth was facilitated by the 2018 Farm Bill federally legalizing hemp and derivatives like delta-8. Most states also allow delta-8 if derived from hemp since it falls in the legal gray area outside delta-9 prohibition.
Delta-8 is commonly sold over the counter in smoke shops, gas stations, online, and elsewhere. It can be purchased in various forms:
- Vape cartridges and disposable e-cigarettes with delta-8 oil
- Edibles including gummies, candies, chocolates, and beverages
- “Flower” that can be smoked – hemp sprayed with delta-8 distillate
- Tinctures, oils, and topical lotions
Many users favor delta-8 because it provides mild psychoactive effects and pain/anxiety relief with less intense cognitive impairment than regular THC. It is also easily accessible in states without recreational cannabis markets.
In 2020 and 2021, Google search interest for delta-8 exploded to 5 to 10 times higher than previous years. Surveys indicate most users are trying delta-8 for recreational purposes rather than therapeutic use.
| Year | Google searches for “delta-8 THC” |
|---|---|
| 2018 | 22 |
| 2019 | 38 |
| 2020 | 237 |
| 2021 | 258 |
Data from Google Trends on search interest for “delta-8 THC” from 2018 to 2021, normalized to a scale of 0 to 100.
Regulatory crackdowns
The booming delta-8 industry has outpaced regulation in most jurisdictions. But a number of states have recently moved to restrict or ban sales.
As of October 2022, 17 US states have imposed limits on delta-8 THC products, citing concerns over unsafe manufacturing processes, lack of research on effects, use by minors, and circumvention of state cannabis laws.
States with total or partial bans on delta-8 include Alaska, Arizona, Arkansas, Colorado, Delaware, Kentucky, Idaho, Iowa, Montana, New York, North Dakota, Rhode Island, Utah, Vermont, Washington and Wyoming.
The FDA has also issued warnings about the dangers of delta-8 THC. They stated delta-8 has psychoactive risks and has not been evaluated for safe use, while raising concerns over contamination in commercially available products.
These regulatory actions demonstrate delta-8 exists in a legal gray area and faces an uncertain future. But for now it remains widely available online and in stores across much of the US.
Research on delta-8 THC
There is far less scientific research on delta-8 THC compared to delta-9 THC. Few studies have looked specifically at the cardiovascular effects of delta-8.
One 1974 study examining different THC isomers found delta-8 increased heart rate but to a lesser degree than delta-9 when administered intravenously in rats.
A 1995 paper reported delta-8 produced weaker heart rate acceleration in rats after injection compared to delta-9 THC and synthetic THC derivatives.
While these results suggest delta-8 may have milder cardiac effects, older animal studies have limitations in translating to expected effects in humans from modern delta-8 products.
An increasing number of case reports and hospitalizations provide real-world data on potential adverse events from delta-8 THC:
- Poison control centers received over 2600 delta-8 exposure cases in 2021, with 17% of those involving cardiovascular symptoms like rapid heart rate, chest pain, and palpitations.
- A September 2022 case report described 2 teenagers hospitalized with acute kidney injury after daily use of delta-8 THC purchased at a vape shop. Both experienced elevated blood pressure and rapid heart rate.
- A case series in Oregon reported 6 patients hospitalized after vaping delta-8 THC. Their symptoms included nausea, vomiting, hallucinations, and tachycardia up to 133 bpm.
These cases reflect that delta-8 products can produce some degree of THC-like toxicity and cardiac effects, but controlled studies in humans are still lacking.
Conclusions on delta-8 THC and heart rate
Based on current evidence, delta-8 THC appears capable of producing transient increases in heart rate and blood pressure, similar to delta-9 THC. The rapid heartbeat, palpitations, and chest pain experienced acutely after using delta-8 are likely caused by its stimulation of cannabinoid receptors.
However, these cardiovascular effects have not been extensively studied in humans specifically for delta-8 THC. Additional research is needed to clarify the potency of its cardiac impacts relative to regular delta-9 THC.
While acute spikes in heart rate and blood pressure from delta-8 are unlikely to be severely hazardous in healthy individuals, those with heart disease or risk factors may suffer greater adverse effects.
The long-term heart risks associated with heavy delta-8 THC consumption also remain unknown at this time. More rigorous studies on the cardiovascular safety of this increasingly popular cannabinoid are warranted.
Until more evidence is available, people with heart conditions should exercise caution with delta-8 use due to its documented ability to influence heart rate and the cardiovascular system through cannabinoid receptors.