{"id":499664,"date":"2026-06-28T14:07:12","date_gmt":"2026-06-28T14:07:12","guid":{"rendered":"https:\/\/www.newsbeep.com\/nz\/499664\/"},"modified":"2026-06-28T14:07:12","modified_gmt":"2026-06-28T14:07:12","slug":"cycling-2x20-did-the-hdrop-calibration-work-outside-and-with-garmin-ciq","status":"publish","type":"post","link":"https:\/\/www.newsbeep.com\/nz\/499664\/","title":{"rendered":"Cycling 2×20 – Did the hDrop Calibration work outside and with Garmin CIQ"},"content":{"rendered":"

\"hDrop<\/a><\/p>\n

I needed to do a threshold session as I\u2019ve been slacking a bit this week. A 2\u00d720\u2032 outdoors workout at below LTHR<\/a> is a standard optimal workout for me, and today was the day to do it. The temperature was around 27 degrees Celsius, with only a bit of wind and very humid. This is going to be a sweaty but enjoyable session.<\/p>\n

A few days ago, I calibrated the hDrop sweat sensor<\/a> with the app\u2019s tool, but I did that after an hour-plus indoor workout that was very sweaty. One problem here is that sweat can linger (pool), so the sensor reads water that\u2019s been there longer than it should. Long story short, after indoor calibration, it could overestimate outdoors.<\/p>\n

I\u2019ll tell you the test results and how the sensor worked when linked to a Connect IQ field on a Garmin Forerunner<\/a>.<\/p>\n

hDrop calibration check and outdoor re-calibration test result<\/p>\n

The current calibration yielded a sweat loss of 151% of the actual weighed loss: the hDrop measured 2.268 L (2.268 kg), and the actual weight loss was exactly 1.5 kg (1.5 L). The previous calibration overestimated by 37%, so the error has grown rather than reduced. You need three qualifying workouts, and I have more than that.<\/p>\n

\"hDrop<\/p>\n

The Garmin Connect IQ data field<\/p>\n

Only one BLE data stream is sent from the hDrop sensor.<\/p>\n

With the sensor connected, you initiate the workout in the app, and the app then connects to your sports device of choice, either a Garmin watch or a Garmin\/Wahoo head unit. Transferring the connection is technically and practically super easy; the faff is in needing to do it in the first place, and I can\u2019t think of any other modern sensor that works this way.<\/p>\n

I\u2019ve tested the hDrop\u2019s link to a Wahoo bike computer<\/a> (it worked), so today was a test to link the Connect IQ field on the Forerunner 970<\/a> (hint: it worked).<\/p>\n

Whilst the app is not very well designed, the watch\u2019s data field is easy to read and looks good. It clearly shows the following:<\/p>\n

Sweat Loss: the amount of fluid your body has lost.
\nSodium Loss: the estimated amount of electrolytes and sodium you are losing.
\nhDrop Score: a proprietary real-time hydration score.<\/p>\n

Putting that into context:<\/p>\n

Typical ranges across metrics<\/p>\n

Metric
\nTypical range
\nWhat it means<\/p>\n

Sweat Loss
\n0.5 to 2.0+ L\/h
\nDriven mostly by temperature, humidity, and exercise intensity. Anything over 2.0 L\/h is considered very high.<\/p>\n

Sodium Loss
\n300 to 1,500+ mg\/L
\nPrimarily determined by genetics. Salty sweaters can easily lose upwards of 1,500 mg per litre of sweat.<\/p>\n

hDrop Score
\n1 to 100
\nA proprietary real-time score. Higher numbers indicate normal hydration; lower scores show accumulating dehydration.<\/p>\n

The image from the end of my workout confirms I sweated 2.68 litres. The sodium loss is very high, confirming what I already knew; I\u2019m a salty sweater, and perhaps that could be linked to the occasional cramps I get. Monitoring dehydration and sodium loss is worth thinking about if you get cramps.<\/p>\n

I\u2019m not entirely sure how to interpret the hDrop\u2019s dehydration status indicated by the third metric. It\u2019s extremely low, and I wasn\u2019t extremely dehydrated.<\/p>\n

\"hDrop<\/p>\n

\u00a0<\/p>\n

Takeout<\/p>\n

In terms of the practicalities of using the hardware, I learnt nothing new today. I did confirm the results of a few trivial indoor setup tests with the Garmin data field, proving that hDrop\u2019s Connect IQ data field<\/a> works in real use.<\/p>\n

However, regarding hDrop\u2019s data and metrics, I\u2019ve raised more unanswered questions. Is the hDrop score of any use? Does the calibration value actually save?<\/p>\n

Quick answers<\/p>\n

Does hDrop work with Garmin Connect IQ?
Yes. The sensor transmits a single BLE data stream, which the Garmin Connect IQ data field picks up and displays as sweat loss, sodium loss, and the hDrop Score in real time.<\/p>\n

How accurate is the hDrop sweat loss estimate?
In this outdoor cycling test, hDrop overestimated fluid loss by 51% against actual body weight change. A previous indoor calibration showed a 37% overestimate, so accuracy varies by conditions.<\/p>\n

What does the hDrop Score mean?
The hDrop Score runs from 1 to 100. Higher numbers indicate normal hydration; lower scores indicate accumulating dehydration. Its real-world reliability is still being assessed.<\/p>\n

Last Updated on 28 June 2026 by the5krunner<\/a><\/p>\n

My favourite kit and nutrition<\/p>\n

Injinji<\/a> \u2013 Runners protect your toes. Avoid discomfort and minor injury. Run more. run faster. I use them.
\nGarmin 90-degree charging adapter<\/a> \u2014 the small adapter that keeps your charging cables tidy. Essential for race day. I use one.
\nGarmin charging puck<\/a> \u2014 the fastest and most reliable way to top up your Garmin before a session. I use one.
\nRavemen FR300<\/a> \u2014 front light that mounts directly under your Garmin or Wahoo head unit. Keeps your bars clean and your beam pointed where it matters. I use one.
\nBody Glide <\/a>\u2013 The Blue anti-chafe stick that all swimmers and many runners use. I use it.
\nMaurten<\/a> \u2014 the race nutrition trusted by elite athletes. Gels and drink mix engineered to be easy on the stomach. I use them.
\nGarmin Varia RTL515<\/a> \u2014 radar rear light that alerts you to vehicles approaching from behind. Pairs with your Edge or Garmin watch. I use this model.
\nFavero Assioma Pro RS2<\/a> \u2014 the power meter pedals most serious cyclists end up choosing. Accurate, easy to move between bikes. I use this model.<\/p>\n

Reader-Powered Content<\/p>\n

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All articles are written by real people, fact-checked, and verified for originality. See the Editorial Policy<\/a>. FTC: Affiliate Disclosure<\/a> \u2014 some links pay commission. As an Amazon Associate, I earn from qualifying purchases.<\/p>\n

\t\t\"the5krunner<\/p>\n

tfk is the founder and author of the5krunner, an independent endurance sports technology publication. With 20 years of hands-on testing of GPS watches and wearables, and competing in triathlons at an international age-group level, tfk provides in-depth expert analysis of fitness technology for serious athletes and endurance sport competitors. ID<\/a><\/p>\n","protected":false},"excerpt":{"rendered":"I needed to do a threshold session as I\u2019ve been slacking a bit this week. A 2\u00d720\u2032 outdoors…\n","protected":false},"author":2,"featured_media":499665,"comment_status":"","ping_status":"","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[6],"tags":[195043,104306,249780,6863,111,139,69,249781,145],"class_list":["post-499664","post","type-post","status-publish","format-standard","has-post-thumbnail","category-technology","tag-connect-iq","tag-garmin-forerunner-970","tag-hdrop","tag-hydration","tag-new-zealand","tag-newzealand","tag-nz","tag-sweat-sensor","tag-technology"],"_links":{"self":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/499664","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/users\/2"}],"replies":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/comments?post=499664"}],"version-history":[{"count":0,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/posts\/499664\/revisions"}],"wp:featuredmedia":[{"embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media\/499665"}],"wp:attachment":[{"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/media?parent=499664"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/categories?post=499664"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.newsbeep.com\/nz\/wp-json\/wp\/v2\/tags?post=499664"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}