Contrast Shower (Hot/Cold) for Cognitive Function

Research suggests that the relationship between cold water exposure and cognitive function is complex and context-dependent, with evidence pointing in different directions depending on the population studied, the type of cold exposure, and whether the exposure is acute or repeated. A 2021 systematic review of 18 experimental studies found that cold exposure impaired cognitive performance in 15 of those studies — particularly attention, processing speed, and memory — even before core body temperature reached hypothermic levels, while a 2025 meta-analysis of over 3,000 adults found some positive downstream effects including stress reduction and quality of life improvements following cold water immersion. A smaller 2019 study of repeated cold immersion sessions suggested that the body may adapt over time, with participants showing improved mental arithmetic performance by the seventh session, though reaction times did not improve and the mechanisms remain unclear. A 2024 study further complicates the picture by indicating that biological sex significantly moderates cognitive responses to cold, with women showing greater declines during cold-air exposure while men were more affected by cold-water immersion on memory tasks. Taken together, the available evidence — which includes systematic reviews, a meta-analysis, and smaller experimental studies — is mixed and limited by modest sample sizes, low participant diversity, and methodological variability, meaning firm conclusions about whether contrast or cold showers reliably benefit cognitive function in healthy adults cannot yet be drawn.