Nicotine is a powerful stimulant alkaloid found naturally in tobacco plants and delivered through various products like cigarettes, vapes, and patches. This substance acts rapidly on the body’s nervous system, causing a cascade of physiological changes. Users often report a distinct feeling of being cold, particularly in their hands and feet. This sensation is a direct consequence of the drug’s effects on the circulatory system and the body’s method of regulating heat.
Nicotine’s Effect on Blood Vessel Diameter
The primary reason for the sensation of coldness is peripheral vasoconstriction. Nicotine rapidly activates the sympathetic nervous system, the body’s “fight or flight” response system. This activation triggers the release of signaling chemicals that cause the smooth muscles surrounding tiny blood vessels to contract.
This contraction leads to a narrowing of the blood vessels, particularly those located near the surface of the skin in the extremities, such as the fingers and toes. This response shunts blood away from the skin and towards the body’s core organs. The significant reduction in blood flow restricts the delivery of warm blood to the body’s surface tissues.
As a result of this reduced circulation, the local skin temperature drops noticeably. Studies using thermography have confirmed this decrease in peripheral skin blood flow following nicotine intake. This drop in surface temperature is what an individual perceives as coldness or clamminess in their hands and feet.
Changes in Heart Rate and Blood Pressure
While nicotine causes peripheral blood vessels to narrow, it simultaneously acts as a potent systemic stimulant on the cardiovascular system. The release of stress hormones, such as norepinephrine and epinephrine, causes the heart to work harder. This leads to an acute increase in heart rate, often by 10 to 15 beats per minute.
Nicotine also causes a transient elevation in blood pressure, typically increasing both systolic and diastolic readings by about 5 to 10 mm Hg. This heightened cardiac activity increases the overall cardiac output, which would typically generate internal warmth. However, the body’s prioritization of blood flow to the central organs overrides this heat generation. The combination of increased internal activity and restricted peripheral flow contributes to the subjective feeling of being cold.
How Nicotine Impacts Core Body Temperature
The subjective feeling of coldness at the skin’s surface is distinct from the body’s core temperature regulation. Nicotine has a central effect on the hypothalamus, which acts as the brain’s thermostat. This central stimulation increases the body’s metabolic rate and energy expenditure.
This process, known as thermogenesis, involves the activation of tissues like brown adipose tissue (BAT), which burns energy to produce heat. Nicotine has been shown to increase core body temperature in a dose-dependent manner. This means that while the extremities feel cold due to restricted blood flow, the overall core temperature may remain stable or even slightly elevated.
The body fights peripheral heat loss from vasoconstriction with central heat production from a stimulated metabolism. This distinction means that the sensation of coldness is primarily a localized skin temperature effect rather than generalized hypothermia. Nicotine creates a complex thermal state where the body is internally warmer but externally cooler.