Sweat & Sodium
Sweat rate & sodium loss.
Weigh yourself naked before and after a 60–90 min steady effort, track fluid intake, and we'll give you the numbers you need to build a real race-day hydration plan.
Typical range 500–1800 mg/L. Use ~1000 if untested.
Sweat Rate
1.30
litres per hour
Sodium Loss
1300
mg per hour
Race-day target
- Replace 60–80% of sweat loss on the bike: aim for 910 mL/h.
- Replace ~910 mg sodium/h via electrolyte mix or salt caps.
- Over a 5-hour 70.3: total fluid ≈ 4.5 L, sodium ≈ 4550 mg.
Test in race-pace conditions (heat, intensity). Sweat rate scales with both — retest in summer and winter.