Which adaptation is a hallmark of cold acclimation that helps preserve core temperature by restricting blood flow to the skin?

Which adaptation is a hallmark of cold acclimation that helps preserve core temperature by restricting blood flow to the skin?

• A. Enhanced vasomotor control with stronger peripheral vasoconstriction
• B. Increased non-shivering thermogenesis
• C. Earlier onset of sweating
• D. Increased sweating

Answer: (A)

When the body acclimates to cold, preserving core temperature hinges on reducing heat loss from the skin. The main way this happens is through vasoconstriction of cutaneous blood vessels, which lowers skin blood flow and therefore decreases heat transfer from the body's core to the environment. In cold acclimation, this vasomotor control becomes more effective: the sympathetic nerves tighten the skin’s arterioles more strongly and more quickly in response to cold. That stronger peripheral vasoconstriction is the hallmark because it directly limits heat loss through the skin, helping to keep the core warmer even when the surrounding environment is cold. Other options touch on heat production or heat loss via sweating. Increased non-shivering thermogenesis adds metabolic heat but doesn’t primarily achieve core temperature conservation by restricting skin blood flow. Sweating or earlier sweating would increase heat loss and is not advantageous in the cold, so they don’t represent the hallmark adaptation in this context.

When the body acclimates to cold, preserving core temperature hinges on reducing heat loss from the skin. The main way this happens is through vasoconstriction of cutaneous blood vessels, which lowers skin blood flow and therefore decreases heat transfer from the body's core to the environment.

In cold acclimation, this vasomotor control becomes more effective: the sympathetic nerves tighten the skin’s arterioles more strongly and more quickly in response to cold. That stronger peripheral vasoconstriction is the hallmark because it directly limits heat loss through the skin, helping to keep the core warmer even when the surrounding environment is cold.

Other options touch on heat production or heat loss via sweating. Increased non-shivering thermogenesis adds metabolic heat but doesn’t primarily achieve core temperature conservation by restricting skin blood flow. Sweating or earlier sweating would increase heat loss and is not advantageous in the cold, so they don’t represent the hallmark adaptation in this context.