<p>Japanese people enjoy bathing, and often soak in deep hot bathtubs up to their shoulders for long periods, from evening to night. However, there have been numerous reports of unexpected deaths related to bathing, especially among older individuals and during the winter months. This review explores the reasons behind these seasonal and age-specific fatalities. Japanese detached houses typically have low insulation and rely on partial, intermittent heating, resulting in cold dressing rooms and bathrooms during winter. Elderly individuals, who often bathe under such conditions, experience significant fluctuations in blood pressure. A nationwide survey revealed that while living rooms may be warm, dressing rooms tend to be cold, and regions with colder dressing rooms report higher bathing-related mortality. Comparative analyses show that elderly people experience a notable increase in blood pressure when undressing in cold environments, even without feeling cold. After immersion in hot water, only the elderly show a sharp rise in blood pressure due to hydrostatic pressure. Despite prolonged exposure to hot water, the elderly do not perceive it as too hot and often bathe for long periods, resulting in hyperthermia. Unlike younger individuals, whose heart rates increase to maintain blood pressure, the elderly show little change in heart rate, resulting in a significant drop in blood pressure during prolonged bathing. When getting up from the bath, peripheral vasodilation leads to further hypotension, known as orthostatic hypotension. These responses can cause the elderly to lose consciousness and submerge their faces in the water, leading to drowning.</p>