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
• 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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