How much water, and when?
A water intake estimate starts from a baseline per kilogram of bodyweight and adds the fluid you lose sweating in training. Litres for today from bodyweight, training time and any extra you add for heat, split across four parts of the day and per waking hour.
Your day
Nothing you type here is sent or stored.
Estimate for today
litres
14 glasses of 250 ml · 220 ml an hour awake
- Morning0.9 L
- Session0.8 L
- Afternoon0.9 L
- Evening0.9 L
- Baseline2.8 L
- Training+0.75 L
- Heat+0.0 L
Your numbers in the formula
How the answer adds up.
A baseline for your bodyweight, plus what training sweats out, plus your own extra.
Step 01
Baseline
L
35 ml × 80 kg, to the nearest 100 ml
Step 02
What you sweat out
L
60 min at 0.75 L an hour
Step 03
Your day
L a day
2.8 + 0.75 + 0.0 L
Reading the result
Sweat varies a lot
The ACSM position stand on fluid replacement reports considerable variability in sweating rates between people (Sawka et al., 2007).
35 ml per kilogram
The baseline is a common rule of thumb and the same figure the QuietGains app uses for its water target. It is not an ACSM number.
Your own sweat rate
The same position stand estimates an individual sweat rate from body weight measured before and after exercise.
Formula and sources
Baseline = 35 ml × bodyweight (kg), to the nearest 100 ml, as the QuietGains app calculates its water target.
Training = minutes ÷ 60 × sweat rate. The three presets are 0.5, 0.75 and 1.0 L an hour for light, average and heavy sweating; they are this page’s choices, since sweating rates vary widely between people [1].
Heat and humidity = the extra litres you enter yourself. The position stand gives no fixed figure for hot or humid conditions, so this page adds none on its own [1].
Total = baseline + training + heat and humidity. The split puts the training fluid in the session and divides the rest evenly across morning, afternoon and evening.
Per hour = total ÷ the hours you are awake, to the nearest 10 ml.
Updated
In the app, a glass is one tap.
QuietGains logs water next to your food, against a target of 35 ml per kilogram.