When temperatures drop, the human body prioritizes the warmth of vital organs like the brain, heart, and lungs, leaving the hands and feet as the first areas to lose heat.
Hein Daanen, emeritus professor of exercise physiology at Vrije Universiteit Amsterdam, explains that blood vessels in the extremities constrict to conserve heat for the torso, a process that is accelerated by the relatively low mass and large surface area of hands and feet.
This heat loss is further intensified by wind, such as when cycling, which carries away body heat. Because the hands remain stationary, they quickly feel the impact of this cooling.
“In extreme cases, I call it ‘circulatory amputation’, where blood flow to the extremities is so drastically reduced that little to no heat is delivered.”
According to Daanen, wearing gloves only helps if they are put on before the hands become cold, as clothing serves to slow heat loss rather than generate it. Because a standard glove is not a heater, it provides no benefit if the hand is already as cold as the surrounding air.
The body handles cold feet differently, and Daanen warns against applying a hot water bottle directly to cold feet. Because cold feet have poor circulation, they cannot effectively absorb or distribute the heat. Cold feet may not send proper warning signals to the brain, creating a risk of burns.
Instead, Daanen suggests placing a heat source near the chest to raise the core body temperature. This action prompts the brain to dilate blood vessels throughout the body, which allows more blood to reach the feet and effectively warm them.
