Personalised hydration: What’s in your sweat and why does it matter?

What is 'sweat testing'?

Knowing how much sodium to replace starts by understanding how much sodium you lose. This is highly unique to each person, with sweat sodium concentrations varying up to 10 times between seemingly similar individuals. In other words, what you lose may be wildly different to your training partner.

For example, Person A’s sweat sodium concentration may be as low as 200 milligrams of sodium per litre of sweat, whereas Person B’s losses may exceed 2,000 mg per litre of sweat.

In this instance, Person A would be classed as a low salt sweater, whereas Person B would be classified as a high salt sweater. Both would be provided with totally different hydration strategies; personalised to their individual requirements. 

With sweat composition varying from person-to-person, hydration shouldn’t be viewed as a ‘one-size-fits-all’ approach and that’s where our Advanced Sweat Test has proven incredibly beneficial.

Sweat testing is an invaluable tool for removing the guesswork and helping you understand a huge part of the hydration equation. The testing itself is a sit-down affair (no exercise required!) and is conducted by applying a harmless chemical called pilocarpine to your forearm using a mild electrical current. This stimulates your sweat glands into perspiring. Your sweat is then collected by a coil of tubing within a macroduct, before being removed and analysed for its sodium concentration there and then. 

It’s simple, painless and takes around 40 minutes. Thanks mainly to genetics, sweat sodium concentration stays mostly stable after infancy, which means you only need to do the test once (solid bang for your buck if you ask us!).  

Are you a salty sweater?

You may now be wondering whether you fit into that 'salty' category? Whilst it can’t be said for certain without a sweat test, those with higher sweat sodium concentrations typically experience the following:

• Underperformance in hot & humid conditions 
• Frequent muscle cramps (during or after exercise)
• Dehydration-related symptoms such as headaches, nausea, sickness
• A persistent fatigue following hard training sessions which fails to dissipate with adequate refuelling and rehydration and feels out of proportion to the effort exerted 
• White (salt) marks on kit
• Feeling ‘gritty’ after drying off post-exercise 
• Sore or stingy eyes due to salty sweat entering them

If any of the above resonates with you, reach out to our expert team for a chat about sweat testing.

Crafting a personalised hydration plan

Having undertaken the sweat test and determined your unique sweat sodium concentration, your practitioner will gather some information about how you sweat, train and (where relevant) compete. Using this, they will then walk you through your personalised hydration strategy that includes electrolyte recommendations that are matched to your individual requirements.

At The Edge HPL, we’ve performed sweat tests on hundreds of individuals ranging from elite level athletes right through to dedicated amateurs and adolescents. Interestingly, we’ve found that the average sweat sodium concentration is ~1,000 mg per litre of sweat and yet many ‘off-the-shelf’ electrolyte tablets provide less than 300 mg of sodium. It’s therefore more than reasonable to think that many people are being short-changed by their electrolyte replacement strategy (i.e. you may not be replacing as much as you need!).

Is a sweat test for you?

Whether you’re an elite athlete pushing the envelope of human performance or a fitness enthusiast looking to optimise your health and fitness, sweat testing is incredibly helpful in understanding your specific hydration needs. Losing too much sodium through sweat without adequately replacing it can impair your energy, performance and recovery.

Here’s what our Advanced Sweat Test will provide you: 

1. An accurate measure of your sodium loss per litre of sweat (your unique sweat sodium concentration)
2. A personalised hydration strategy 
3. Reduced risk of dehydration 
4. Reduced risk of muscle cramping
5. Improved concentration and reaction times 
6. Resources to help you calculate your sweat rate

To enquire about Sweat Testing at our private facility in Surrey, UK please click here.