Bearded Goat Gear

Real World Trail Running & Backpacking Gear Reviews

hDrop Gen 2 Hydration Sensor Review hDrop Gen 2 Hydration Sensor Review
hDrop Gen 2 Hydration Sensor Review

I recently got the hDrop Gen 2 wearable, and reusable, hydration sensor to measure my sweat and electrolyte loss while doing long runs. Before we get into the details, here’s my quick thoughts after several weeks of hands on use.


  • Easy to use
  • Up and “running” in a few minutes
  • No extra fees or parts needed
  • Helpful report given after each exercise


  • Cost seems high at first (no consumables means lower cost over time)
  • Requires phone connection – phone needs to be with you

Ok, that said, let’s get into the details on this interesting little device.

hdrop gen 2 wearable hydration sensor review

As longer distance trail runners, we are very interested in hydration and how we can improve both hydration and fueling to make our runs more enjoyable and to be able to run longer or faster, or both if we’re having a good day!

For myself, I’ve had some runs and races where things get out of whack and I end up a bit nauseous or just don’t feel great…and that’s not a ton of fun.

I’m a solid middle of the pack runner, I’m not chasing the top 3, and I want to enjoy my runs, feel good while doing them, and get better over time.

I was pretty surprised to hear about wearable hydration sensors when listening to a podcast a few months back and started digging into the topic.

First I came across the Nix Biosensors hydration monitor system, but was put off by the use of one-time “pods” that you have to replace every time you use it. While not a huge cost, at $5 a pop at the lowest price, it would add up over time when added to the base cost of $129.

After looking around some more I came across hDrop and they happened to be taking orders for their Gen 2 system that had no single use parts – bingo!

If you’ve got questions about your hydration, wonder what your electrolyte loss might look like, and want to improve your hydration before, during, and after activities, then this might be the thing you’ve been looking for.

Use code ADAMHYDRATE and get 20% off your hDrop Gen 2

hdrop gen 2 wearable hydration sensor review

As mentioned above, my favorites so far with the hDrop system are:

  • Easy to set up and start using
  • Helpful report post workout
  • No recurring fees or parts needed

Video Review

Unboxing and Opening

The hDrop Gen 2 arrived in a fairly non-descript but tidy little package, and opening it up revealed a well put together box with the sensor, arm bands, instructions, and the little carry pouch.

Once I got the parts out of the mailer and box, it was time to put it together and get it working.

You can find the apps by scanning the QR code on the lid of the box. Get that downloaded and then follow their setup instructions – be sure to do this BEFORE you go for your first workout as you’ll need to create an account and login. This is difficult to do if you’re in the hills and don’t have reception. Ask me how I know.

Once you’ve got everything unpacked, you can select from one of two arm bands depending on the size of your upper arm.

A quick aside: the upper arm is where this device needs to be worn, as it’s been calibrated for that area. I was not aware of this, but it didn’t represent any special issues – just something to be aware of.

Using The hDrop Gen 2

Once I had it setup, I went out for a run, remembering to bring my phone along as it’s needed for recording the data.

This for me means I need either be heading out for a longer run and wearing a vest, or I need to wear something like a flip belt in order to record the data from the sensor while out for a run.

Depending on what activity you’re doing this might be trivial or a bit of a pain. Just don’t forget your phone and open up the app to start recording before you begin.

Post Workout Report From The hDrop Gen 2

After ending the workout via the app, you get a report with quite a bit of information. Of immediate interest to me, having never had a sweat test done, was my overall sweat rate and my electrolyte loss data. You can see what it looks like below; I found out that while I was sweating a “regular” amount, my electrolyte loss rates were very high and it recommended a hydration plan to keep me on track.

Quick note that data can also be exported in CSV and JSON formats.

Connecting Your Watch To The hDrop Gen 2

It turns out that you can connect your hDrop Gen 2 to a Garmin watch that has access to the Garmin app store. There’s a few big caveats to this…

  • You need to find and install the app from the Garmin store onto your device. This isn’t too difficult using your phone.
  • You’ll then start a workout on your phone, tap the gear icon, select “Connect to Garmin”
  • Now you need to select the hDrop app from the Garmin activities and keep it open. If you exit this screen it stops the app.
  • To reconnect the hDrop to your phone, you’ll need to exit the app on your Garmin device and on your phone select to reconnect with the phone.
  • When you do this, your phone needs to have a data connection to upload the data.

Here’s what the helper screen shows in app:

hdrop gen 2 how to connect to garmin devices - instructions from hdrop app

To me, this means that you cannot run a Garmin activity app like running alongside the hDrop app. Perhaps you could start that first and then run the hDrop app, but you can’t leave the hDrop app or that will completely stop. For now, I’m not going to use the watch connection and will just use it on runs where I have my phone with me.

While asking hDrop support about another question I found out the following – big news and really excited to see this integrated:

Big Garmin update coming soon to see all data in real-time and get data directly on Garmin Connect.

Battery Life

The websites says that the Gen 2 has a 36 hour active battery life and I’ve used it for several runs before needing a recharge. I can’t confirm the battery life, but I’ve taken it out for single runs of several hours and had no issues.

It does lose charge as it just sits on your shelf, so be aware you might need to plug it in if you haven’t used it in a week and you want to use it on your Saturday long run.

Fortunately it has a USB C charging port, comes with a USB-A to USB-C cable, and charges up quickly.

The cover for the charging port isn’t especially snug and is not connected; I expect to lose it before too long – I would expect them to update this in the future.

Recording time

As of writing this, the longest time it can record for is 4 hours.

However, I was told by support that this will be extended to 12 hours in the coming months.


The kit comes with a few alcohol wipes that they suggest using after workouts. I’ve also used some isopropyl alcohol (91%) and a piece of paper towel to keep it clean from time to time.


Overall I’m very happy with the Gen 2 and have been using it regularly. With the coming updates to Garmin and activity length, it’s going to correct a couple of issues that were annoying but not deal breakers at the time I got the product and started using it.

It’s been easy to use, provided quick feedback, and the data is presented in an easy to understand manner with the ability to export in case you want to get nerdy with the data.