Do you know how much you sweat?
The body continuously loses fluids during a workout session in the form of sweat. Not replacing back these fluids can easily lead to dehydration! Dehydration can occur at any time, but it is especially important and beneficial when exercising. Studies have shown that just a small amount of dehydration can have negative impact on athletic performance and may lead to heat illness. Dehydration occurs when fluid loss (via sweat, urine and through respiration) is greater than fluid intake (via drinking and food). One way to determine how much fluid you need to drink during a workout is by measuring your sweat rate. Sweat rate is the amount of fluids that you lose through sweat during a workout session. Don’t worry, it is not a rocket science but a simple and easy calculation which can help you perform your best.
How to calculate your Sweat Rate?
Calculating the sweat rate is very simple and consists of this procedure:
Do a warm-up to the point where you start sweating.
Urinate if necessary.
- Weigh yourself on an accurate scale. Work out for a specific amount of time (1 hour easiest, but 30 minutes can work if you simply multiply your end sweat rate by two, giving you your sweat rate per hour)
- Drink a measured amount of your beverage of choice during the workout
- Do not urinate during the workout
- Weigh yourself again wearing EXACTLY what you wore during the initial weighing
A. Pre-exercise weight=___________________ [kg]
B. Fluid consumed during exercise= ___________________ [L]
C. Post-exercise weight= ___________________ [kg]
D. Weight change= Pre-exercise weight _____ [kg] – Post-exercise weight _______ [kg] =________
E. Exercise time= ___________________ [hours] F. Sweat Rate= [Weight change _____ [kg] + Fluid intake ______ [L] / ______ [hours] = _________ [Liters/hours]
The final number (F) is your sweat rate, or the amount of fluid that you lose through sweat during a specific amount of exercise (usually expressed per 1-hour). This should help you determine the amount of fluid you should be drinking during and after your workouts.
Key points to remember
- Sweat rates generally increase after 10-14 days of heat exposure, so sweat rate should be re-calculated following heat acclimatization.
- Higher sweat rates are generally found in men and those that are highly fit.
- Temperature plays a role in sweat rate, so calculations should be done for different environments (winter vs. summer OR hot vs. cold spaces).
- When first beginning an exercise routine in heat, your body loses more sodium through sweating, so slightly increase the amount of sodium in your diet until you’ve become adapted (after 10-14 days).However, be judicious with the sodium intake if you are hypertensive.
NOW YOU CAN CALCULATE YOUR OWN SWEAT RATE!