Raynaud's syndrome, also known as Raynaud's disease, causes reduced blood flow to extremities in response to cold or stress. This leads to color changes and numbness in fingers and toes.
Growing up in the Pacific Northwest, I dreaded ski trips every winter. My fingers and toes would lose sensation as I waited on the cold chairlift, worsened by my anxiety about heights. When a Raynaud's attack occurs, my fingers lose all color, turning pale, then purple and blue, before flushing red when blood returns. The pain is so intense that I often have to shake my hands to ease the discomfort.
Raynaud's symptoms can even occur during hot weather. For example, Courtenay Harris Bond experienced numb, discolored fingers after cooling down rapidly following a run on a warm day in August.
“The blood flowing back into my fingers feels like they’re being smashed in a door.” — a runner and coach with Raynaud's, earlier this year
During an attack, capillaries constrict, drastically reducing blood flow and causing severe discomfort as circulation returns.
Raynaud's syndrome can cause painful and unsettling symptoms triggered by cold or stress, but it rarely poses serious health risks.
Author’s summary: Raynaud's syndrome causes painful color changes and numbness in extremities triggered by cold or stress, significantly impacting daily life though it is typically not dangerous.