Studies show that marijuana can make you feel dizzy because it lowers your blood pressure.
One of the most commonly reported side effects of marijuana is dizziness, especially when standing up. In one study, 28% of participants experienced dizziness after marijuana use.
Scientists believe this is because marijuana lowers blood pressure, reducing blood flow to the brain.
While dizziness is common, it is often preventable. By staying hydrated, eating enough, and changing positions carefully, you can reduce your risk for marijuana-induced dizziness.
What Causes Dizziness?
When a person stands up, their blood pressure normally drops due to the effects of gravity. Many people call this a “head rush.”
In a medical context, this is called orthostatic hypotension and it frequently occurs in healthy individuals. However, it is most common among the elderly and those with low blood pressure.
Usually the body will quickly adapt to a change in posture. It does this by increasing the heart rate and releasing hormones. When you stand up, these reflexes act to boost blood pressure levels 10% higher than when sitting to compensate for the change in gravity.
The brain also adapts to changes in blood pressure in order to maintain enough blood flow when a person stands up. When the body is not able to adapt, and the brain loses blood flow, dizziness and fainting can occur.
These symptoms are a way to restore normal blood flow to the brain and maintain homeostasis. For example, when you’re dizzy, you’ll often sit down. This change in posture helps regulate blood flow and restore balance.
Fainting is a more extreme version, where a severe change in blood pressure causes the body to involuntarily collapse to restore normal blood flow.
Marijuana’s Effects on Dizziness
Marijuana can cause lower blood pressure and subsequently a lack of blood flow to the brain, leading to dizziness.
Marijuana contains many active compounds that have different effects on the body. Both mind-altering THC and non-psychoactive CBD may act to lower blood pressure.
According to a 2017 review, the THC in marijuana can cause a drop in blood pressure. A 2004 study found that a chemical that acted similarly to CBD also caused a drop in blood pressure. Lightheadedness is commonly listed as a side effect of CBD.
Scientists still haven’t uncovered exactly why marijuana leads to dizziness, but we know it has to do with blood pressure and posture.
One theory is that marijuana widens the blood vessels leading to the brain. In a seated position, this increases blood flow to the brain, but in a standing position, the decreased blood pressure leads to decreased blood flow.
What Do Studies Say?
A 1992 study measured blood flow and circulation in 10 healthy volunteers after smoking marijuana. The participants smoked the marijuana (or placebo) in a reclining position.
The researchers measured them both in a reclining position and while standing. 6 out of the 10 subjects reported feeling moderate to severe dizziness in the standing position, but none of them felt dizzy while reclining.
The 3 participants who reported severe dizziness experienced a drop in blood pressure below 60 mmHg at least once while standing.
60 mmHg is believed to be the lower limit of the brain’s reflexes – blood pressure that falls below this level is known to cause a lack of blood flow to the brain.
This study revealed that posture makes a big difference in how marijuana causes dizziness.
How To Prevent Dizziness
There are a few things you can do to reduce your chances of experiencing marijuana-induced dizziness.
First, stay hydrated. Blood volume and blood pressure are directly related, and hydration levels can help maintain a healthy blood volume.
Second, eat regularly. Low blood sugar can contribute to low blood pressure. Dietary sodium and other electrolytes also contribute to maintaining a normal blood pressure.
Finally, don’t get up too fast. If you smoke marijuana in a seated position, take your time getting up. This gives your body more time to adjust to the changes and prevent dizziness.
If you do get dizzy when smoking marijuana, find somewhere to sit down or, even better, lie down until the feeling passes. It’s also a good idea to drink some water and have a snack. When you feel better, make sure to move slowly and listen to your body.
Dizziness is most likely to occur in inexperienced or new marijuana users without a tolerance. Studies have shown that marijuana users with a tolerance are less likely to experience side effects. So it’s important to be more cautious when trying marijuana for the first time, or when coming back from a hiatus.
With a few small changes, you can reduce the likelihood of experiencing dizziness when using marijuana.