Cold can trigger a sharp stress response, followed by a slower pulse as the initial shock eases, Kevin Tracey explains. In this Levels discussion, Tracey describes people monitored during sudden cold exposure. He also shares his own experience with cold showers. For our [Cold Exposure for Mental Resilience]( /health-practices/mind-nervous-system/cold-exposure-for-mental-resilience) community, the key point is that shift from shock toward calm. At first, heart rate rises. Blood and urine samples show a strong fight-or-flight response: the body’s sudden reaction to a threat. Tracey says heart rate can then slow during continued exposure. Sometimes, it falls below Resting Heart Rate. The excerpt gives no exact pulse changes or timing. Tracey also discusses whether cold might reduce inflammation. He says he found very few strong human studies. Just one or two studies supported a link between cold, a slower pulse, and less inflammation. That is limited support, not proof of a lasting benefit. His personal account adds another layer. The cold still hurts his skin, but it starts bothering him less. That feeling matters to him. It does not establish that cold builds lasting resilience outside the shower. For members already tracking this habit, numbers and feelings offer different pieces of the picture. A session note could pair pulse readings with how uncomfortable or calm you felt. Comparing those notes across sessions—and with community peers—may reveal patterns worth following. A slower pulse alone does not prove lower inflammation or better stress tolerance. What changes have you noticed in your pulse and sense of calm during cold exposure?