The question of whether quitting cannabis can lower blood pressure (BP) is common, particularly as the substance’s use becomes more widespread. The relationship between cannabis use, cessation, and BP regulation is not a simple one, as the body’s cardiovascular system responds differently during active use, in the immediate aftermath of quitting, and over the long term. Understanding these distinct phases is necessary to grasp how cessation ultimately affects vascular health. The impact of stopping use depends on the duration and frequency of past consumption, as the body adjusts to functioning without the influence of cannabinoids, particularly delta-9-tetrahydrocannabinol (THC).
Cannabis Use and Blood Pressure Regulation
Active cannabis use immediately influences the cardiovascular system, primarily mediated by the psychoactive compound THC. Acute administration of THC typically causes an initial, dose-dependent increase in both heart rate and BP. This effect is a result of sympathetic nervous system activation, which temporarily constricts blood vessels and increases the force and speed of the heart’s contractions.
However, with chronic, heavy use, the cardiovascular system can develop tolerance to these acute effects. Over time, heavy users may experience a phenomenon called orthostatic hypotension, which is a sudden drop in BP upon standing up, due to decreased vascular resistance. This paradoxical effect in chronic users stems from the complex interaction of cannabinoids with the body’s endocannabinoid system.
Recent and frequent cannabis use has been associated with a modest but detectable increase in systolic BP in large-scale population studies. This suggests that while tolerance to the acute spike may develop, the underlying chronic use can still exert a hypertensive effect on the circulatory system. Furthermore, long-term cannabis use has been linked to an increased risk of mortality related to hypertension.
Acute Cardiovascular Changes After Cessation
In the immediate period following the abrupt cessation of heavy cannabis use, a temporary increase in BP can occur in a subset of individuals. This effect is a physiological response known as a rebound effect, as the body’s systems adjust to the sudden absence of the drug. Studies involving daily users have shown that during abstinence, systolic BP can increase by up to 22.8 mmHg and diastolic BP by up to 12.3 mmHg in some cases, compared to periods of active use.
This temporary hypertension is considered part of the withdrawal syndrome, which often involves a transient increase in sympathetic nervous system activity. Other symptoms, like anxiety and heart palpitations, are also manifestations of this temporary autonomic imbalance. The rise in BP and heart rate is typically most pronounced in the first days to weeks after quitting, corresponding to the peak intensity of withdrawal symptoms.
These initial fluctuations are not the long-term outcome of cessation, but a short-term adjustment phase. For individuals with pre-existing hypertension, this transient spike in BP can be clinically significant and necessitates careful monitoring.
Long-Term Blood Pressure Normalization
The long-term effect of quitting cannabis for many individuals is the sustained normalization and reduction of BP. Once the initial withdrawal phase passes (typically within a few weeks), the body begins a deeper process of cardiovascular recalibration that takes months. This long-term improvement is rooted in the normalization of the endocannabinoid system’s influence over vascular tone and sympathetic drive.
Chronic cannabis exposure can alter the function of cannabinoid receptors (CB1 and CB2) located throughout the cardiovascular system, contributing to chronic vascular stress and inflammation. Cessation allows the body’s intrinsic endocannabinoid system to reset its signaling pathways, which gradually helps restore healthy blood vessel dilation and constriction. This reversal of vascular dysregulation is a primary mechanism for the sustained reduction in BP.
The sustained absence of THC also reduces the chronic activation of the sympathetic nervous system that can occur with frequent use. The lowering of this overall sympathetic drive results in decreased peripheral vascular resistance and a more relaxed state for the heart and arteries. This full normalization often requires a period of several months, reflecting the time needed for complete systemic recovery.
Related Cardiovascular Improvements from Quitting
Beyond the direct systolic and diastolic BP measurements, quitting cannabis results in other significant improvements in cardiovascular health metrics. One notable change is a reduction in the resting heart rate (RHR) over time. Chronic cannabis use often elevates RHR, and cessation allows the heart to operate more efficiently at a lower baseline, reducing overall cardiac workload.
Another metric that often improves is heart rate variability (HRV), which is an indicator of the balance between the sympathetic and parasympathetic nervous systems. While some users report an initial dip in HRV during the acute withdrawal phase, the long-term trend is toward improved HRV. This signals a healthier, more balanced autonomic nervous system and is associated with greater resilience against cardiac events.
For those who consumed cannabis by smoking, cessation removes the cardiovascular burden associated with smoke inhalation. Cannabis smoke contains many of the same toxins and irritants as tobacco smoke, which can increase carboxyhemoglobin levels. This reduces the blood’s oxygen-carrying capacity and increases myocardial oxygen demand. Quitting smoking removes this source of pulmonary and cardiac stress, allowing chronic inflammation in the lungs and vasculature to begin healing.