Calculating Sodium & Fluid Loss
Using weight pre-workout, post-workout, and fluid intake as a gauge for fluid loss in a training session can help you determine how much fluid and sodium you need to replenish.
Pre-Workout
- Weigh Yourself
- Weigh yourself in minimal clothing before starting your workout. Note this as your pre-workout weight.
During Workout
- Track Fluid Intake
- Keep track of the amount of fluid you consume during your workout. This can be done by measuring your drinks before and after consumption.
- Monitor Workout Conditions
- Note the temperature, humidity, and intensity of your workout, as these factors affect your sweat rate and fluid loss.
Post-Workout
- Weigh Yourself Again
- Immediately after your workout, weigh yourself again in the same minimal clothing. Note this as your post-workout weight.
- Calculate Fluid Loss
- Initial Weight (A): Pre-workout weight
- Final Weight (B): Post-workout weight
- Fluid Intake (C): Amount of fluid consumed during the workout
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Use the formula
Fluid Loss = (A−B) + C
Example
- Pre-Workout Weight 70 kg
- Fluid Intake During Workout 1 liter (1000 ml)
-
Post-Workout Weight 69 kg
Fluid Loss= (70 kg−69 kg) + 1 liter = 2 liters
- Sodium Loss Estimate
- Sweat rate: 2 liters
- Sodium loss: 500-1000 mg per liter
- Total sodium loss: 1000-2000 mg
Sodium Replenishment
- Estimate Sweat Rate
- Based on your fluid loss, estimate your sweat rate. For most people, sweat contains about 500-1000 mg of sodium per liter of sweat.
- If you lost 1kg (2.2lbs) (approximately 1 liter) of fluid, you lost around 500-1000 mg of sodium.
- Restore Sodium
- Use a drink that contains sodium or sodium supplement (Replenish) as needed.
- For a more precise approach, you can get your sweat tested to determine the exact sodium concentration and adjust your replenishment strategy accordingly.
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