Every now and then I like to dive into the new tech and gadgets that pop up in the health/fitness industry. Since Justin and I got into the nitty gritty of proper hydration for endurance athletes last summer, it was pure luck (and search algorithms) that put an ad for a biosensor in front of me last Fall. 

I got myself on a pre-order list for the Nix Hydration Sensor. It is a biosensor that analyses sweat during workouts to give the user an informative breakdown of their sweat volume and concentration. The volume is measured in oz/hr and concentration provides electrolyte loss in mg. This was a perfect step in the direction of helping ourselves and our athletes manage their race nutrition/hydration. Last year we discussed the importance of proper volume of fluids and sodium during training/racing and the notion that most athletes chronically under-fuel and then underperform. Our research had given us general guidelines but this Nix Biosensor provides even more personalized data in raw numbers.

DISCLAIMER: I have no connection to or benefit from this company and its product. I paid for this sensor on my own and am detailing my initial review purely for informational purposes. 

Which brings me to the cost. The sensor goes for $129 and comes with 4 single-use patches. They do offer refill packs which are $25 for 4 patches. The price seems a bit steep considering the patches are single-use only. However, after playing around with it and thinking it through, it’s not something I really consider necessary for each workout. Ideally, I only need to know my sweat rate for specific climates. Cold weather vs warm weather and more humid vs less humid. In addition, hard interval workouts vs steady state. The work rate certainly changes the sweat rate. Once I get that information I can see myself cataloging the info and then planning accordingly. 

Once I decided how many patches I needed (I ordered a bunch of refill packs because I wanted to play around) I ordered it up and waited. Upon delivery, the unboxing was pretty cool. Sleek design and cool colors (black and green have also been our company’s race colors). The sensor is small enough and patches light enough that you don’t notice it while exercising. The sensor comes in a carrying/charging case that uses USB C and holds charges for > 8 hrs. Once you put it back in the case it will charge it as well. But as I said, the patches are single use so you discard them after each use. I even accidentally left it on when Justin and I did a bike-run brick workout but stopped and started the sensor tracking between each. The result was a very skewed run result because the sensor had already accumulated about 2 hours worth of sweat from the bike. So the patch MUST be swapped out for each activity. 

The app is pretty neat and straightforward. It allows you to sync the sensor with your phone and then a user-friendly interface takes you through step by step to name your sensor, start/stop workouts, allow push-notifications to devices like watches and bike computers (solid feature IMO), and then analyze your workouts and sweat profile. It gives you a breakdown of how much sweat you lost in oz/hr and how many mg of electrolytes you lost per hour and per oz of sweat. It really does keep it simple because that’s all you need. The electrolyte loss is total in aggregate. It does NOT break down each type lost. But that’s ok because sodium is really the only one I’m worried about. And the push notifications can be useful to someone who wants to know in the moment how they are doing and drink/replenish accordingly. The caveat here is you must have your phone on your in order to get the push notifications to your device. 

I will say for the price, this Nix Biosensor is well-worth the amount of personalized information I’ve received. After using this thing for a couple of months I have made drastic changes to my endurance nutrition because previously accepted “general guidelines” had me about 50% lower than what I actually need in terms of fluids and electrolytes. That certainly could explain my frequent flyer miles to the med tent post-races. 

My only issue aside from the cost of refill patches is their software. The app is frustrating in terms of pairing it with my sensor and then uploading the info after a workout. Sometimes it pairs automatically and transfers within moments. But then other times I’m spending 5-10 min trying to get it to pair and have to log out in order to get it to work and then it takes almost 5 minutes to transfer data after a workout. Length of workout does not seem to be an issue here as Justin and I did this side by side after a 2hr ride and his upload was almost instantaneous and mine took 4+ minutes. I’ve talked to them about this and hopefully, they square this on their software side. 

Currently, the sensor is programmed for cycling and running. The app lets you choose indoor or outdoor. It is not submersible which means swimming is a no-no but I imagine it can really be used for any workout on land. I did try it on some soccer players and it offered them equally as good info. 

All in all, I’m super happy with this purchase and I’ve found more than enough useful information for my training. Even if the data isn’t 100% accurate, it’s got to be in the ballpark and my immediate changes seem to have paid off. So I’m going in the right direction for sure. It’s also more user-friendly than some of the other products out there because I don’t have to use a gauze pad or mail it away for my results. I think I’d give this Nix Biosensor a solid 4.3/5 stars. If they managed to sort out the software hiccups and even offer more of a sweat breakdown then it’s a grand slam for the ROI and ease of use. 

Stay tuned for more breakdowns. You KNOW you’re curious about my sweat. 

Happy Training!