Deep Dive Digest #27: The Future of Garmin Wrist Metrics, Samsung Lags Apple & Five Free Weekly Intel Feeds
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A new analysis ranks 40 metrics that the optical sensor on Garmin and Apple watches could theoretically read based on published scientific literature, from heart rate through to blood oxygen, skin temperature, hydration status and beyond. Blood sugar sits at the bottom of the list: possible in principle, years away in practice. The full ranking is on site and it is worth reading before the next wave of wearable marketing arrives.
Samsung launched its Galaxy Watch range this week. Across four comparison pieces on site the picture is consistent: Samsung’s core hardware components: battery, display brightness, charging speed, sit where Apple Watch was one to two years ago. The Galaxy Watch Ultra 2 is a capable device that needs to play catch-up.
Fitbit’s new device format has a name. The Fitbit Edge has appeared in leaked images with a 7-day battery. It positions Google’s tracker line between the Fitbit Air and a more capable fitness band. Polar has pushed a meaningful firmware update across six watches: trend graphs, a custom button, and an 80% charge limit. For a brand that had gone quiet, it is a signal worth noting. The HoloSwim 3 Pro has produced the first publicly available GPS track from swim goggles in open water, tested on site.
The site now publishes five free weekly intelligence feeds, each covering a distinct corner of the industry. They are comprehensive summaries, not daily inbox clutter, and they are all free. Legal Files covers court decisions and patent verdicts. Trademark and Patent Filing tracks what companies are registering before they announce. Regulatory Filing tracks device certifications and FCC submissions before launch. Fix Files rounds up confirmed bugs and workarounds across all major brands each week. Feature Files covers new firmware improvements across Garmin, Amazfit, Coros, Polar, Wahoo and others. All five are in the Forum section of the site. Start with Feature Files: the5krunner.com/category/deep-dive-feature-files
Garmin Prime Day Deals: Epix Pro 47% Off, Fenix 8 27% Off
Amazon’s October Prime Day is live. The Garmin Epix Pro is 47% off and the Fenix 8 is 27% off in the USA, with more Garmin watch and Edge deals in the UK and Germany.
Garmin and Apple Future PPG Sensor Metrics: 40 Ranked
The optical sensor on Garmin and Apple watches could read 40 things beyond heart rate. See what ships today, what is coming, and why glucose is last.
Polar 2026 Feature Update: Trend Graphs, Custom Button and 80% Charge Limit
Six Polar watches now show a week of sleep, HRV and recovery trends on the wrist. Firmware 6.0.18 also adds a configurable Custom button, full sport settings on the watch and an 80 per cent charge limit.
GPS Swim Goggles – First Ever GPS Track For Open Water
Holoswim 3 Pro becomes the first public GPS track from swim goggles in open water, tested against the Garmin Fenix 9 Pro and Apple Watch Ultra 4.
Which sports watch brand looks after you best?
A new comparison of nine sports watch brands, judged on how the company treats you after you buy.
Samsung Galaxy Watch Ultra 2 vs Apple Watch Ultra 4: Which to Buy?
The phone in your pocket decides this one: Galaxy Watch Ultra 2 does not work with an iPhone and Apple Watch Ultra 4 does not work with Android. Here is what each side of that fence gives an athlete in battery, GPS, health sensors, diving, safety and price.
Samsung Galaxy Watch 9 vs Galaxy Watch Ultra 2: Full Comparison
Galaxy Watch Ultra 2 lasts twice as long between charges as Galaxy Watch 9, is the only one of the two that fast charges, and is built for harder use. It comes in one large 47mm size, so wrist size decides the matter for many athletes.
Samsung Galaxy Watch Ultra 2 vs Galaxy Watch Ultra: What’s New
Galaxy Watch Ultra 2 has an 800mAh battery, faster charging, a brighter display and a dive certification, but Samsung quotes the same 60 hours of everyday battery life as the original. Owners of the original Ultra do not need to upgrade, and a discounted original still suits some new buyers.
Galaxy Watch vs Apple Watch Charging Speed: Who Is Ahead?
Apple Watch Series 12 and Ultra 4 reach 80% in 30 and 45 minutes, while Galaxy Watch Ultra 2 reaches 40% in 30 minutes and Galaxy Watch 9 has no fast charging. Longer battery life closes much of that gap for Ultra 2, and the EP-OL715 charger is explained in…
Galaxy Watch upgrade guide: Watch 4, 5, 6, 7 or 8?
Samsung Galaxy Watch 9 vs Galaxy Watch 8: What’s New
Galaxy Watch 9 has a 20 per cent larger battery in the 40mm size and a new Snapdragon chip, but Samsung quotes the same 30 hours as Galaxy Watch 8. Most of the new health features also reach Watch 8 by software update, so Watch 8 owners should keep what…
#1 Legal Files: Week Ending 6 October 2026
A federal judge in California has ordered Apple to pay Masimo a further $184 million in interest on the $634 million Apple Watch patent verdict. This week’s Legal Files explains the order, where the case stands and what it could mean for Apple Watch owners.
#15 Deep Dive Feature Files: Week Ending 3 October 2026
A weekly summary of new firmware features and improvements across Polar and Hammerhead. Bug fixes excluded. Week ending 3 October 2026.
#0 Trademark & Patent Filing: September 2026
Whoop filed four trademarks in September 2026: WHOOP CONNECTED CARE in the medical services class, and WHOOP ONE, WHOOP PEAK and WHOOP LIFE for its membership tiers. Patents include a Whoop muscle oxygen sensor, an Oura ring with a removable battery and a Google cuffless blood pressure method.
#0 Regulatory Filing: September 2026
The founding issue of Regulatory Filing covers September 2026. Suunto’s OW265, reported to be the Race 3S, reached the FCC, Garmin filed several unnamed models, Polar’s H12 heart rate monitor appeared in Brazil and Apple’s five Apple Watch grants arrived with its autumn launch.
#18 The Deep Dive Fix Files: Week Ending 2 October 2026
This week covers Fenix 8 heart rate loss on 23.39, a Fenix 8 Pro map download stuck at 51 percent, SuuntoPlus Guides not syncing, Garmin Express on Mac failing with Fenix 9 Pro, a full Edge Explore 2 blocking map updates, Fenix 9 firmware 6.38 bugs and Fenix 7 installing…
The Deep Dive Podcast
Listen to one of our recent discussions on the Deep Dive podcast – EP79 Huawei Watch D3: Does the Blood Pressure Science Actually Work? (ft. AI Insights)
Browse every edition in the Deep Dive Digest archive.
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Last Updated on 7 October 2026 by tfk the5krunner
Small things I always use
- Garmin 90-degree charging adapter: Charges your Garmin from any USB-C cable. Essential when travelling. I use one.
- Body Glide: The blue anti-chafe stick swimmers and runners carry. I use it.
- Speedo earplugs: Fewer ear infections and no cold-water dizziness. I use them.
- Dryrobe Advance: My winter changing robe for open-water swims. I use one. A cheaper option is the AONYIYI changing robe.
- Maurten: Race fuel that stays easy on the stomach. I use them.
- Garmin charging puck: The quickest way to top up before a session. I use one.
- Injinji: Toe socks that stop rubbing, so you run more. I use them.
- Ultimate toe protectors: Stop black toenails on long runs. They work. I use them.
- Compressport R2 v2 calf sleeves: My calf sleeves of choice. I use them.
- Cellucor C4: My pre-workout before hard sessions.
- TPU tubes: Schwalbe Aerothan, Tubolito and Pirelli SmarTube. Light, tiny spares. I use all three.
- G8 insoles: Adjustable insoles that are good. I use them.
- Cycplus Cube: A 97g electric pump that gets a road tyre rideable in two minutes. I carry one. 5% off with code THE5KRUNNER.
Watches and sensors
- Polar H10: My daily driver for waking HRV.
- Polar Verity Sense: My backup arm-worn HR sensor.
- Nomad bedside charger: Charges my iPhone and Apple Watch overnight. I use it, and many of their bands.
- Train.Red: The best muscle oxygen sensor I’ve used.
- Tymewear: Accurate heart rate and reliable ventilatory zones. I use it to pace endurance rides over an hour.
- Garmin Forerunner 970: A pro-grade triathlon watch. I use this.
- Apple Watch Ultra 4: My daily smartwatch. No phone needed on rides.
- Garmin Fenix 9 Pro: I’ve just bought one.
On the bike
- Continental GP5000 for everyday riding, and Aero 111 on the front for special occasions.
- Helmets: Specialized S-Works Evade 3 for road riding, and Rudy Project Wing for TT-style races. I use both.
- Ravemen FR300: A front light that mounts under your Garmin or Wahoo. I use one.
- Wahoo TRACKR Radar: I use it on one bike and Varia on the other. They perform the same.
- Garmin Varia RTL515: Radar that warns you of cars from behind. I use this model.
- Wahoo ELEMNT Roam 3: The bike computer that’s easy to use. I use mine on most rides.
- Favero Assioma Pro RS2: Accurate power pedals that swap easily between bikes. I use this model.
Home and indoor training
- NPE Runn: Makes my basic treadmill smart, sending more accurate speed and distance to my watch and Zwift. I use it.
- Google Wifi: Keeps Zwift connected in my pain cave. I use it.
- Apple TV 4K: Zwift on the big screen. I use two.
- Google Nest Doorbell (wired, 2nd gen): My video doorbell, running in both Google Home and Apple Home. I use it.
Health, recovery and sleep
- FreeStyle Libre 3 Plus: Shows how my blood sugar responds to diet.
- hDrop: Measures my sweat loss in summer and indoors.
- Fourth Frontier Zone: Checks my heart under load in hard sessions.
- Oura Ring 5: My partner’s recovery tracker of choice.
- Kineon MOVE+: Red light therapy for niggles. It works.
- Eight Sleep: A cooling mattress cover my partner and I use nightly.
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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
