Dizziness, which can manifest as lightheadedness, unsteadiness, or a spinning sensation known as vertigo, is a common side effect reported during cannabis intoxication. The state of “being high” refers to the psychoactive effects that occur after consuming cannabis, primarily due to delta-9-tetrahydrocannabinol (THC). This feeling of being off-balance is rooted in distinct physiological reactions within the body. Understanding these mechanisms clarifies why cannabis use temporarily disrupts a person’s sense of equilibrium.
How Cannabis Affects Blood Circulation
The primary physiological mechanism causing dizziness after cannabis use involves the cardiovascular system’s response to THC. Tetrahydrocannabinol acts as a vasodilator, meaning it causes blood vessels to widen, which subsequently reduces vascular resistance throughout the body. This expansion of the circulatory space results in a temporary drop in overall blood pressure, a condition known as hypotension. When blood pressure lowers significantly, it can momentarily reduce the blood flow and oxygen supply reaching the brain, leading to lightheadedness or feeling faint.
Acute cannabis consumption often results in a temporary increase in heart rate, known as reflex tachycardia, as the body attempts to compensate for the drop in blood pressure. This compensatory mechanism is often insufficient, especially when a person changes position quickly. The most frequent manifestation of cannabis-induced dizziness is orthostatic hypotension—a rapid drop in blood pressure that occurs upon standing up from a sitting or lying position. This delay in regulating blood pressure against gravity results in a transient lack of cerebral blood flow, causing unsteadiness or a head rush.
The drop in blood pressure is particularly pronounced in individuals who consume high doses of THC. In some cases, the pressure drop can be severe enough to cause presyncope or even fainting, especially in those with pre-existing cardiovascular sensitivities. The cardiovascular effects are mediated by THC’s interaction with the endocannabinoid system, which regulates autonomic functions like heart rate and vascular tone. These circulatory changes are a direct, dose-dependent consequence of the psychoactive compound entering the bloodstream.
Other Systemic Factors Causing Dizziness
Beyond the direct effects on blood circulation, dizziness from cannabis is also influenced by THC’s interaction with the central nervous system (CNS). The endocannabinoid system has receptors located in brain regions responsible for balance and coordination, such as the cerebellum and the vestibular system. THC can temporarily impair the function of the vestibular system, the sensory system in the inner ear that provides the brain with information about motion, head position, and spatial orientation.
This neurological interference leads to disequilibrium, a feeling of unsteadiness, or a true sensation of spinning known as vertigo. The temporary disruption of spatial processing contributes to the feeling of being off-balance, even when a person is seated. The intensity of this effect is linked to the concentration of THC used, as high-potency products are more likely to overwhelm the system and produce pronounced effects on balance.
Several systemic conditions associated with cannabis use can further compound dizziness. Dehydration is a common contributing factor, as the dry mouth sensation known as cottonmouth can lead to decreased fluid intake. Reduced body water volume makes it harder to maintain blood pressure, intensifying hypotensive effects caused by THC. Similarly, consuming cannabis on an empty stomach can lead to a drop in blood sugar levels, which independently causes lightheadedness and disorientation. Combining these factors creates a multifaceted systemic reaction that increases the likelihood and severity of dizziness.
Immediate Actions to Address Dizziness
If a person begins to feel dizzy or lightheaded after consuming cannabis, the first and most practical step is to immediately sit or lie down. This action removes the gravitational challenge on the circulatory system, allowing blood flow to the brain to normalize quickly and preventing a potential fall or injury. Once settled, the person should remain still and take slow, deep breaths to maintain a sense of calm and regulate heart rate.
Hydration is an immediate and effective countermeasure; drinking water or non-alcoholic fluids can help restore blood volume and mitigate dehydration. Consuming a light snack containing sugar, such as a piece of fruit or crackers, can stabilize blood glucose levels if low blood sugar is contributing to lightheadedness. Avoid standing up too quickly once the dizziness subsides, opting instead for slow, deliberate movements.
While cannabis-induced dizziness is typically temporary and resolves on its own, medical attention should be sought if symptoms are severe, prolonged, or accompanied by other worrying signs. Seek professional help if the dizziness leads to fainting, or if it is associated with persistent vomiting, severe chest pain, or symptoms that do not improve after resting and hydrating.