Login | April 26, 2025
Sweat loss measuring devices
PETE GLADDEN
Pete’s World
Published: April 14, 2025
I’ve always been amazed by how quickly engineers, researchers and bioscientists have been able to take large and expensive high-tech laboratory devises that are used in assessing human physiology and engineer them down into small, portable and cost-effective devices which can be utilized outside of a lab environment.
Now not only have I seen this phenomenon happen with heart-rate monitors, but I’ve also witnessed it with power meters, blood lactate measuring devices, stress quantification mechanisms and sleep monitors to name but a few.
And well, over the past couple of years I’ve watched with interest the refinement of yet another portable physiological assessment device that can be used outside the lab. I’m talking about portable sweat loss monitors.
Sweat loss measuring devices (aka SLMDs) have now given athletes the ability to monitor their homeostasis in real time - due to the fact that sweat loss plays a critical role in thermoregulation and skin hydration.
Therefore, via this new hydration monitoring technology, athletes can actually track their water and electrolyte loss to further enhance their ability to reach peak performance while training and racing.
So back during the stone-age when I was competing and we didn’t have hydration monitoring technology, it wasn’t at all uncommon to loose so much fluid and electrolytes that you’d become dehydrated, fatigued and worse.
Yup, those were the good old days when severe cramping and hitting the wall with a big fat bonk was a commonplace occurrence.
And then there’s those worse case scenarios where you could get so mentally discombobulated and disoriented that you might suffer physical injury due to severe fluid imbalances.
And the real kicker here is that research back then had already established that sweat sodium loss could vary dramatically between individuals, so there wasn’t a one-size fits-all strategy for fluid/electrolyte replenishment.
I for example sweat profusely, so my fluid and electrolyte loss has always been up on the high side of the scale, yet I never really knew exactly where I needed to be with relation to how much I’d lost and how much I would need to ingest for replacement.
Thus, sometimes I’d get it right, other times I’d get it wrong and bonk, and still other times I’d go overboard and have to much liquid sloshing around in my gut.
But it wasn’t just one’s sweat rate you had to think about, you also had to take into consideration exercise intensity, exercise length, environmental temp and dew point and diet.
Thats why having a training device that can give you an on-the-spot analysis of your hydration status is an absolute godsend.
Okay, so to understand how these devices work let’s dive into a smidge of science here.
Now there are a couple different types of sweat glands - the eccrine and apocrine - that reside in the dermal layer of our skin, and they secrete sweat and metabolic waste products such that thermal equilibrium can be maintained throughout the body.
And it’s the eccrine secreted sweat that contains all sorts of great markers - like glucose, lactate, urea, sodium, potassium, Vitamin C, Zn2+, Ca2+, cortisol, estrogen and various proteins - which can be evaluated by these portable sweat measuring devices.
The evaluation of all those markers can then provide you with real-time information on your hydration status.
Now there are currently two types of sweat monitoring devices available, one is in the form of epidermal patches, temporary tattoos and fabric sensors which adhere to the skin, while the other is rigid wearable devices.
Several of the more popular devises include Hdroptech hDrop Gen 2, Liipoo AbsolutSweat hydration biosensor, Nix hydration biosensor, GECA hydration watch, BSX LVL Hydration Sensor, Gx Sweat Patch and the Flowbio S1.
Now the good news is that most of these devices will not cost you an arm and a leg to obtain. The aforementioned range from under $100.00 to a bit over $300.00.
Finally, here are three important things to keep in mind if you’re shopping for one of these devices.
1. Consider your budget and the features that each device can provide you relative to its cost.
2. Determine how accurate you want your data to be. The more you pay, generally the better the data.
3. How simple/complicated is the device to use. If you’re a data freak, spend more and study more. If you just want general information, spend less and study less.