The sensation of feeling cold or experiencing shivers after consuming cannabis is a widely reported phenomenon known colloquially as “weed chills.” The primary psychoactive compound in cannabis, Delta-9-tetrahydrocannabinol (THC), temporarily alters the body’s temperature regulation system. This article will explore the underlying biological mechanisms that cause this chilling effect.
THC’s Impact on the Body’s Thermostat
The main reason people feel cold after using cannabis traces back to how THC interacts with the brain’s temperature control center. This center, a small region deep within the brain called the hypothalamus, acts much like a thermostat, maintaining the body’s internal temperature. The hypothalamus coordinates responses like shivering or sweating.
THC exerts its influence by engaging with the Endocannabinoid System (ECS), a complex network involved in regulating numerous functions, including temperature. THC strongly binds to the CB1 receptors, which are highly concentrated in the hypothalamus. This interaction disrupts the normal signaling pathways that regulate the body’s temperature.
When THC activates these receptors, the hypothalamus temporarily resets the body’s temperature set point to a lower level. This effect is known as THC-induced hypothermia, typically a mild and short-lived drop in core body temperature. The brain perceives the current temperature as too high and initiates cooling mechanisms to match the new, lower set point.
This lowering of the temperature set point also involves a decrease in the body’s metabolic rate, which reduces the amount of heat the body naturally produces. Because the body is actively trying to cool itself down, it creates the physical sensation of being cold or having the chills. Research suggests this response is dose-dependent, meaning higher concentrations of THC are more likely to produce a noticeable cooling effect.
The Role of Peripheral Blood Flow
The body’s immediate physical response to the hypothalamus resetting the temperature manifests in changes to blood flow. To shed heat, the body must reduce the circulation of warm blood near the skin’s surface. This reaction affects the peripheral vasculature, the blood vessels farthest from the body’s core.
THC can induce peripheral vasoconstriction, causing the small blood vessels in the extremities, such as the hands and feet, to narrow. This narrowing restricts the flow of blood to the skin, minimizing heat loss to the environment. The reduced blood flow makes the hands and feet feel cold to the touch and contributes to the feeling of being chilled.
The combination of the brain perceiving a lower target temperature and the physical constriction of peripheral blood vessels creates the full experience of “weed chills.” This is the body’s attempt to achieve the new, lower thermal balance dictated by the effects of THC. Although the overall core temperature drop is slight, the concentrated reduction in surface blood flow is what the body registers as a cold sensation.
Immediate Steps to Warm Up
If the cold sensation becomes uncomfortable, simple steps can be taken to override the body’s temporary attempt at cooling. The quickest way to feel warmer is to change your immediate environment by moving to a warmer room or adjusting the thermostat.
Physical actions that involve covering up are effective ways to feel warmer:
- Wrapping up in a blanket or putting on additional layers of clothing.
- Consuming a warm, non-alcoholic beverage to help raise internal temperature.
- Engaging in light physical activity, such as a short walk, to encourage better blood circulation.
- Taking a warm shower, as the heat directly warms the skin and encourages blood vessels to widen, counteracting vasoconstriction.
These measures help the body quickly return to a comfortable temperature, minimizing the duration of the cold sensation while the body’s central thermostat naturally returns to its normal set point.