Hydration Calculator
Use this calculator after a training session to measure your sweat and sodium losses, and get a personalised rehydration plan using Pulse products.
How to get accurate results
Weigh yourself before your session in minimal clothing, bladder empty, before drinking anything.
Track your fluid intake during the session. Note how many ml you drink.
Weigh yourself again immediately after in the same conditions, before eating or drinking anything post-session.
Enter your numbers below to get your sweat loss, sodium loss, and rehydration plan.
Session details
Environmental conditions (optional, improves sodium estimate)
Your session results
Total sweat loss
—
Sweat rate
—
Total sodium lost
—
% bodyweight lost
—
Your rehydration plan
During session
After session
—
Start hydrating before you feel thirsty. Thirst lags behind actual dehydration by 1 to 2% bodyweight. By the time you feel it, performance is already dropping.
Sweat rate calculated as: (Pre-weight minus Post-weight plus Fluid consumed in litres) divided by session hours. Sodium loss estimated at 500 to 1000mg per litre of sweat depending on intensity and temperature. Sodium concentration stays flat at 20 degrees C and below. During-session sodium replacement target is approximately 50 to 60% of total losses, with the remainder replaced post-session. Individual sweat rates vary. Run this test across multiple sessions for a more accurate baseline. This calculator is a guide only.
