As an endurance athlete who’s competed in triathlon races of all distances, competitive cyclist, and (most recently) Jiu Jitsu practitioner, I’ve always struggled with hydration and mineral replacement.
I’ve used tried and true methods to measure my sweat loss, the most basic one is to measure your weight before activity then measure again after you’re done and add in the weight of everything you’ve drank to get a gross sweat loss weight. However, I’ve never been able to calculate how much salt and minerals get depleted during workouts and races, often leading to an annoying phenomenon called Basal Displacement which occurs when minerals loss is severe enough that everything you drink post workout (despite added electrolytes) pretty much goes right through and you end up going to the bathroom a lot.
Coach Kurt recently let me borrow his Nix Solo Hydration Monitor to test. The Nix comes with a wearable patch that you place on your bicep and a rechargeable sensor unit that locks into the patch. The sensor does all the monitoring and synchronizes to the Nix app on your phone. After the workout your data is synchronized for analysis, offering insight into sweat loss rate along with sodium and electrolyte loss to help you dial in both your mineral and hydration needs for performance within workouts along with recovery from them.
The patches are expensive. They run about $6.50 each but I’ve been able to keep the same patch on for the past three workouts that included a bike ride, a HIT workout, and a rather spicy 45min Jiu Jitsu training session during which I was sure the unit would torn off my art, but it survived just fine. I’ll keep using the same patch while it continues to work! But, the cost of patches are a major concern. I shaved the area, wiped it clean with alcohol which I let dry, then slapped on the patch and rubbing it to ensure a firm connection.
Another concern is data loss. Several users have mentioned data connection loss and inability to recover data, which means you just used up one of the $6 patches and walked away with no data — not to mention the cost of the workout itself that you might have to repeat in order to collect data.
On the positive side, using the Nix monitor not only confirmed my rather ridiculous sweat loss rate, arming me with valuable information on how much to drink per hour of exercise, but (perhaps most importantly) invaluable information on mineral loss that historically challenged me in the past. For example, if you finish a workout, drink liquids to rehydrate, and find yourself going to the bathroom a lot, and I mean a lot a lot a lot!, then changes are your mineral balance is off and your body is unable to properly absorb liquids to help you rehydrate. In this case, knowing how much salt and other electrolytes to consume during your activity will help limit your overall mineral loss such that your physiology will recover faster from replenishing loss during work periods.
So the big question is, is it worth the cost? For me, the answer is yes because the utility of information is worth the cost of purchasing and ensuring the unit works, despite missed opportunities of unconnected monitor, data loss, and forgetting to start a workout on the Nix unit. Having this invaluable insight into mineral loss will have a positive impact on my consumption during workouts as well as consumption post training to aid recovery. For someone who has severed health/physical needs tied to hydration and/or mineral loss, cost is subjective to the utility they gain from this non-invasive device.
We are not affiliated with Nix by the way.
Nix Biosensor: https://nixbiosensors.com/pages/nix-solo-individual-app