Nutrition
Hydration
The baseline is roughly 30-35 ml per kilogram of body weight, and every hour of hard training adds 0.5-1 litre. Work out your daily number.
Why bother
As little as 2% dehydration measurably cuts strength and endurance, and thirst lags behind the loss. A calculated target lets you drink on schedule instead of chasing thirst in the evening.
In the app: Tabata Timer by fit.how has these calculators built in, plus an interval timer you can read from across the gym. See the app.