Your Cart is Empty
Beat the Heat: Understanding Sweat Rate and Optimising Hydration for Summer Training
A
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:
-
Sweat loss (litres) = (Pre-ride weight -Post-ride weight) + Fluid intake - Urine output
Determine sweat rate:
-
Sweat rate (L/hr) = Sweat loss / Duration of the ride in hours
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:
-
Pre-hydration: Consume 450ml– 700ml of fluid 2 hours before exercise.
-
During exercise: Aim to replace 80-100% of fluid lost through sweat.
-
Post-exercise: Rehydrate with 1.5 times fluid lost.
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:
|
Electrolyte |
Recommended Amount (per hour) |
|
Sodium |
400–700 mg |
|
Potassium |
100–200 mg |
|
Magnesium |
20–50 mg |
|
Calcium |
50–100 mg |
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:
-
Sodium: ~600–1000 mg
-
Potassium: ~100–200 mg
-
Magnesium: ~20-50 mg
-
Calcium: ~50-100 mg
-
Carbohydrates (optional): ~20–30g/hour (recommended for endurance training)
Why this matters:
-
Sodium is the most critical electrolyte for rehydration—it helps retain fluid and triggers thirst.
-
Potassium and magnesium help prevent muscle cramps.
-
Calcium supports nerve signalling and muscle contractions.
-
Carbohydrates can aid in endurance if training exceeds 90 minutes.
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
-
SiSHydro Range –Convenient electrolyte drink mix designed for performance hydration.
-
Moisture-Wicking Apparel: Brands like Rapha and Pactimo offer base layers designed to manage sweat effectively during intense sessions.
-
Sweat Monitoring Tools: Devices like the Gx Sweat Patch provide real-time data on sweat rate and electrolyte loss, aiding in personalised hydration strategies.
-
Vacmaster Cardio54 Indoor Cycling Fan- adjustable targeted airflow that helps you control your heart rate and keep your core temperature down.
Note: Always consult with a healthcare or nutrition professional before making significant changes to your hydration or nutrition plan.
Also in Performance
Wattbike X UA Next
The Under Armour Next Academy at Battersea Power Station offers a comprehensive testing facility designed to push athletes to their limits through a series of six athletic tests, each targeting different aspects of fitness.
This facility focuses on empowering and testing the next generation of athletes through a series of assessments, including those on the Wattbike, which is used to measure key cycling metrics, such as power output, endurance, and fitness levels.
How to Improve VO2 Max
Improving VO2 max means increasing your body’s effectiveness at using oxygen for exercise. Also known as VO2 peak, training this aspect can help to improve your endurance and output, whether training for a local race or just improving your fitness. Improve your VO2 max with indoor bike workouts designed by sports scientists.
Read More
How to Complete Cycling Time Trials on an Indoor Trainer
Time trials allow you to test your pace, performance, and monitor your goals. It tests your ability to ride fast. Our guide takes you through the benefits of performing your cycling time trials on your indoor trainer.
Read More