Consuming cannabis often reduces the sensation of sweating or leads to a feeling of being cooler. This phenomenon, known scientifically as anhidrosis, results from how the active compounds interact with the body’s internal temperature controls. The change involves a complex biological mechanism that temporarily alters the central nervous system’s command center for temperature regulation. Understanding this effect requires looking into the body’s standard cooling processes and the influence of the cannabis plant’s compounds on regulatory systems.
The Body’s Standard Thermoregulation Process
The body maintains a stable core temperature through thermoregulation, which is centrally managed by the hypothalamus in the brain. This area acts as the body’s thermostat, constantly monitoring internal temperature and initiating responses to keep it within a narrow, healthy range. When internal temperature rises above this set point, the hypothalamus triggers mechanisms to dissipate heat. One primary cooling response is the activation of the sympathetic nervous system, which controls the eccrine sweat glands. These glands secrete a mixture of water and salts onto the skin’s surface. As this moisture evaporates, it carries heat away from the body, leading to a cooling effect. The sympathetic nervous system also manages vasodilation, expanding blood vessels near the skin to increase blood flow, allowing heat to radiate into the environment.
Understanding the Endocannabinoid System
The Endocannabinoid System (ECS) is a widespread molecular signaling network present throughout the human body, serving as a major homeostatic regulator. Its primary role is to maintain internal stability across numerous physiological processes, including mood, pain-sensation, appetite, and temperature regulation. The ECS consists of three main components: endogenous cannabinoids, receptors, and enzymes. Endogenous cannabinoids, or endocannabinoids like anandamide (AEA) and 2-arachidonoylglycerol (2-AG), are naturally produced lipid compounds that act as neurotransmitters. These molecules bind to specific receptors to initiate signaling cascades. The two main receptors are Cannabinoid Receptor Type 1 (CB1) and Cannabinoid Receptor Type 2 (CB2). CB1 receptors are densely concentrated in the central nervous system, particularly in the brain. CB2 receptors are found predominantly in the peripheral nervous system and immune cells. The action of cannabis is driven by its compounds, known as phytocannabinoids, which mimic the body’s own endocannabinoids to interact with these CB1 and CB2 receptors.
How Cannabis Influences Sweat Gland Activity
The primary psychoactive component in cannabis, delta-9-tetrahydrocannabinol (THC), acts as a partial agonist on the CB1 receptors. Because the hypothalamus possesses a high concentration of these CB1 receptors, THC is able to directly influence the body’s thermoregulatory center. When THC activates CB1 receptors in this region, it effectively lowers the thermoregulatory set point. This downward shift causes the body to believe its core temperature is lower than it actually is. Consequently, the brain reduces or inhibits the necessary signals for cooling mechanisms, including the sympathetic outflow to the eccrine sweat glands. The result is a decrease in the initiation of sweating, leading to the observed anhidrosis or reduced perspiration. This mechanism explains why individuals may feel a slight drop in core body temperature, known as drug-induced hypothermia.
Other Related Physiological Effects
The observed reduction in sweating is one manifestation of the widespread modulation of the Autonomic Nervous System (ANS) by cannabis. The ANS controls involuntary body functions, and THC’s influence on the CB1 receptors impacts several systems simultaneously. For instance, the common side effect known as “cottonmouth,” or xerostomia, results from THC binding to CB1 receptors in the salivary glands. This binding inhibits the release of acetylcholine, a neurotransmitter that normally stimulates saliva production. Similarly, cardiovascular effects such as an increase in heart rate, or tachycardia, are observed due to THC’s action on CB1 receptors in the peripheral nervous system. These accompanying effects confirm that cannabis compounds broadly influence involuntary control systems.