Taking cold showers for 30 days can have various effects on the body. Initially, the shock of the cold water can increase alertness and improve circulation. Over time, cold showers can boost immunity by increasing the number of white blood cells. They can also improve mood and decrease levels of stress and anxiety. Additionally, cold showers can promote weight loss by activating brown fat, which burns calories to generate heat. Overall, cold showers have numerous positive effects on the body and can greatly benefit overall health and well-being.