Dehydration, Rehydration, and Impact on Physiology

"The HDR Protocol is a 12-day, sequential fluid manipulation intervention designed to assess the physiological effects of controlled changes in hydration status. The protocol consists of three consecutive 4-day phases:~Hydration Phase (Days 1-4): Participants follow a standardized fluid intake protocol designed to promote and maintain a euhydrated state. Hydration status is monitored using objective measures such as urine specific gravity and body mass.~Dehydration Phase (Days 5-8): Participants adhere to a fluid-restriction regimen to induce a hypohydrated state. The level of dehydration is verified through the same hydration status measures to ensure consistent and safe hypohydration.~Rehydration Phase (Days 9-12): Participants resume the standardized fluid intake protocol used during the Hydration Phase to restore euhydration. Rehydration effectiveness is confirmed through repeated hydration assessments."