What causes goosebumps?

Have a medical-related question you’ve always wanted answered? The doctors at Madison Health are here to help! Email your ‘Ask the Doctor’ questions to news@eastidahonews.com and they might end up in our weekly column.

QUESTION: What causes goosebumps?

ANSWER: Our evolutionary ancestors had a lot more hair on their arms and bodies. When a sudden cold draft occurred, tiny muscles in their arms and legs would involuntarily contract, causing the hair follicles to stand on end, making the hair barrier taller and more firm against the onslaught of frigid air.

In today’s world, humans have evolved to have much less hair, but those tiny muscles still exist, and when our bodies sense a chill in the air, they tighten automatically, as though they would extend the little hair we have into some sort of defensive shield against the cold. This reaction is similar to that of other creatures in nature – porcupines with their quills which stand up when they sense danger; cats whose hair stands on end when they’re frightened, etc. Even without much arm hair, goosebumps still serve a purpose.

The flexing of the tiny muscles brings more heat to the skin, the raised hair follicles cause the pores to close, and even the tiniest hairs, when standing on end, help keep warmth close to the skin.