He continued: “Although the low fluid group did not report being thirstier than the high fluid group, they had darker and more concentrated urine, clear signs of poor hydration. An important observation was that poor hydration was associated with greater cortisol reactivity to the stress test. Exaggerated cortisol reactivity to stress has been associated with poor long-term health.”
The study explains that dehydration triggers the release of vasopressin, a hormone that helps the body retain water but also activates the brain’s stress-response centre, increasing cortisol production. Sustained vasopressin release can strain the kidneys and heighten stress responses.
The researchers conclude that staying hydrated could help the body manage stress more effectively. “Being hydrated may help your body manage stress more effectively,” said Dr Kashi. He advised that a simple way to check hydration is by monitoring urine colour, light yellow typically indicates good hydration.