SPORT SCIENCES FOR HEALTH, cilt.1, ss.1-12, 2025 (ESCI)
Purpose The purpose of the present review was to highlight changes in human athletic performance, cognitive function, and
brain hemodynamics associated with exercise and heat induced fluid loss of ~1–3%. Hypohydration is the most common
aspect of dehydration. Although the impacts of dehydration on human athletic performance, cognition and cerebral blood
flow have been widely discussed, immediate effects of mild or moderate hypohydration are not clearly understood.
Methods A database literature search was conducted in PubMed, Science Direct, and Scopus. The studies published between
2013 and 2025 were explored in these databases. The selected studies were included in the PRISMA diagram after the
screening and exclusion processes.
Results Thus, 594 studies were found in the initial screening. After the inclusion criteria were met, 21 studies were examined.
Conclusion Mild or moderate hypohydration led to disturbances in human athletic performance, muscle power output, endur-
ance, and neuromuscular system, as well as cerebral hemodynamics and cognitive functions. Moderate hypohydration was
found to be associated with increased prefrontal hemodynamic responses, which might be an indicator of impaired neuronal
efficiency. Also, the alterations in cerebral hemodynamics were closely linked to exercise type, intensity, and environmental
factors.