The Diet Hydration Calculator estimates post-exercise fluid replacement from measured body-mass change, fluid consumed, and urine produced during a session. Unlike a general daily water target, it focuses on sweat loss and recovery from a specific workout.
The result reports sweat rate and a replacement range. Measurement error can be substantial when clothing is wet, the scale is inconsistent, or intake is not recorded. People with fluid restrictions or medical conditions should follow individualized clinical guidance.
Use minimal dry clothing and the same scale.
Include water and sports drinks during the session.
Dry off and use comparable clothing.
Include any urine passed between the two weigh-ins.
A value above 100% allows for continued urine loss during recovery.
Use repeated sessions in similar conditions to build a personal range.
Where:
Assumptions: The method assumes body-mass change mainly reflects fluid balance during the measured session.
The result estimates fluid to consume during recovery based on measured exercise losses.
Avoid rapid overconsumption. Seek individualized advice for fluid restrictions, kidney or heart disease, or recurrent exercise illness.
Given:
Calculation:
Sweat loss = 70.0 − 69.4 + 0.5 − 0 = 1.1 L. Sweat rate = 1.1 ÷ 1 = 1.1 L/h. Replacement = 1.1 × 1.25 = 1.375 L.
Result: About 1.38 L of post-exercise replacement fluid.
Replacement should be spread over recovery rather than consumed all at once.
A factor above 100% accounts for continued urine production during recovery.
No. Repeat in different temperatures, intensities, and clothing conditions.
The inputs indicate fluid intake exceeded measured losses or there was measurement error.
Long, hot, or high-sweat sessions may require sodium replacement, but individual needs differ.
It is intended for exercise-specific losses. Use a daily water planner for baseline intake.