Beat the Heat: Understanding Sweat Rate and Optimising Hydration for Summer Training

As summer temperatures rise, so does the challenge of training and trying to maintain optimal performance. With the heat, sweat loss can lead to dehydration, reduced endurance, and impaired recovery.  

Understanding your sweat rate and implementing effective hydration strategies can be a simple way to help you gain the edge in your training.

CALCULATING YOUR SWEAT RATE 

Before we can improve our hydration strategy we must first understand our sweat rate and how it varies based on factors like temperature, humidity, intensity, and individual physiology. Knowing your sweat rate can help give you a tailored hydration strategy to prevent dehydration.  

Here's a simple method to calculate it: 

Pre-ride weight: Weigh yourself nude before your ride. 

Post-ride weight: Weigh yourself immediately after the ride, again nude. 

Fluid intake - Measure the volume of fluid consumed during the ride. 

Urine output - If you urinate during your training session, estimate the volume. 

* This is the best practice and should be followed as closely as possible. While perfect precision isn’t always feasible, consistency is key - use the same approach every time you test.

Calculate sweat loss: 

Determine sweat rate: 

This calculation provides a personalised sweat rate, essential for developing an effective hydration strategy you can utilise for specific training sessions and the duration of your rides.  

It's best to do this test in multiple conditions so you know for future rides your specific sweat rate. This gives you an accurate measurement as to how much you’ll need to drink during and post-exercise to replace essential electrolytes and fluids to beat dehydration.  

MANAGING SWEAT RATE: HYDRATION AND NUTRITION STRATEGIES

 
Dehydration can significantly impair performance. Studies indicate that even mild dehydration can lead to a 22-48% drop in endurance. To combat this:  

ELECTROLYTE BALANCE 

Sweat contains essential electrolytes like sodium, potassium, calcium, and magnesium. Replacing these is vital to prevent muscle cramps and maintain fluid balance.   

For most people on average, especially those training for more than 60 minutes, here are the general guidelines per hour of exercise: 

Pro Tip: If you're a heavy sweater or see white salt stains on your kit, aim for the upper range of sodium (closer to 700–1000 mg/hr). 

IDEAL INGREDIENT RATIOS FOR ELECTROLYTE DRINKS 

When purchasing or mixing your own electrolyte drink mixes, aim for a balanced formulas that reflects your sweat losses. The ideal electrolyte ratio (per litre of fluid) should look like this when you are purchasing any electrolyte products: 

Why this matters: 

TAILORING INTAKE TO YOUR SWEAT RATE 

Once you’ve calculated your sweat rate (see our guide above), use that number to estimate how many mg of sodium and other electrolytes you’re losing per hour. That allows you to build a personalised hydration plan, critical for maximising performance, recovery, and comfort on the bike. 

RECOMMENDED PRODUCTS TO SUPPORT HYDRATION & REDUCE SWEAT LOSS 

Note: Always consult with a healthcare or nutrition professional before making significant changes to your hydration or nutrition plan.