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ck2

bet marathoners and ultra runners will start using this to improve performance

(don't have a problem with that, but it's predictable)

too bad it's not "wearable" like a watch but that might be coming eventually too since Garmin has a patent on it

* https://the5krunner.com/2026/02/06/garmin-non-invasive-blood...

(btw Fenix 9 launched today but it's same hardware as Fenix 8 and no glucose feature)

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Amateur cyclists already wear CGMs, and as a type 1 myself, they see mine and start asking all about CGMs. It must be so boring for them to worry about fluctuations between 85 and 120.

I don’t think amateur cyclists will have much to gain from this other than satisfying their curiosity.

Before buying one, just know that fit cyclists will appear glucose intolerant on a CGM. See Fig. 1 at https://pmc.ncbi.nlm.nih.gov/articles/PMC10933193/

There has been talk, but as one who hangs around those circles I've not heard of anyone actually doing it. But I'm sure someone is. At the same time, what I'm reading is that CGM won't give a non-diabetic any actionable information.

a regulated blood sugar level aids massively in cellular repair, inflammation reduction, and immune response. These are well studied and established. I could absolutely see a top athlete using AID in the future as part of a recovery routine, but I can also understand reluctance to adopt anything new or weird.

A few years back, there were a number of startups that essentially resold prescriptions of the ABT/DXCM CGM and provided personalized meal/exercise-response analytics on top. Seems like traction has been tough going, though. Dialing back from "anyone with potential metabolic issues" -- what's a realistic market? Something like high-level athletes and/or bio-hacker enthusiasts are the only folks who seem to care. On the low end, the OTC options are eating away as well.. they are less accurate, but probably solve the use case better for a pre-diabetic "once-a-year/occasional" wear use case.

Talking to ultramarathoners and cyclists, I think lactate is a biomarker that is tracked (POC blood samples) and would be more immediately useful for training/performance. AID might be construed as a form of doping, IMO.

Lactate actually comes for free with blood glucose when you measure it with a chemical sensor, it's just not something that's usually asked for. I definitely think it would be considered a form of doping to use it in competition, but I think recovery is where it would make more impact anyways. You also wouldn't want to use it before a race, as you'd run the risk of reduced pancreatic function.

AGC will find its main application in surgical and inpatient uses, eg in cardiac, neuro, burn, ICU, and people with diabetes in any hospital setting.

There doesn't seem to be a continuous lactate sensor on the market. Lactic acid production and/or clearance are definitely useful data w.r.t. exercise (many training regimens talk about lactate thresholds) and also useful in in-patient settings.

No disagreement about AGC in the hospital -- there is a lot of lab/titration work in current clinical workflows for monitoring patient glucose levels.

Lactate's available in the internal engineering data of these sensors, just not something that anyone has wanted to spend the time or money to qualify with the FDA. It essentially comes "for free" due to the chemical reaction the sensor uses.

I think you are misinformed: the electrochemical reaction used by continuous glucose sensors relies on a glucose-specific enzyme and it doesn't have anything to do with lactate. Lactic acid strips use a completely separate enzyme/reaction.

Hat tip to you and sibling comment about continouous lactate sensors (seem like they are microneedle/patch based?). Quick review shows minimal clinical evidence, but maybe that's sufficient for the consumer wearable market.

I've had the fortune to work with several CGM OEMs behind the scenes as part of our work developing an artificial pancreas, they all have a secret lactate signal!

There doesn't seem to be a continuous lactate sensor on the market.

They exist, a simple search will turn up a variety (how well they work is a different question). But see my sibling comment, they're banned from cycling competition.

To follow-up, "commercially available" products from a simple search appear to all be vaporware. I did see that cyclists have been estimating lactate thresholds through breathing rate/expiration volume measurements

I definitely think it would be considered a form of doping to use it in competition

Already banned:

https://www.bikeradar.com/news/uci-bans-supersapiens

I am curious how this will help. During training? During the actual race, the strategy is to eat a much as you can without puking.

I am aware of the "eating wins races" strategy for endurance sports.

Glucose and ketone monitoring seems a natural, more precise extension of that strategy. Isn't the point of carb-cramming to get more glucose into your blood stream, where your muscles can convert that into forward motion?

Yes. But you don't need to monitor glucose levels to do this. Because it's well known you can productively use as much as you could manage to consume (without vomiting). So all the device will ever tell you (if you're in the middle of significant endurance event) is that you need to raise your blood sugar. It'd be no more actionable than a writing 'your blood sugar is low' on your hand with a sharpie.

> to improve performance

How? Like, what is the mechanism where this is useful?

Monitoring glucose and ketones can help you develop metabolic flexibility and let you grok how easily your body cuts over to ketones. Knowing your personal realtime glucose and ketone levels helps you understand just how much carbs will kick you out of ketosis or keep you in it. Glucose monitoring will help you avoid large crashes that can lead to low energy. Among other things!

More on metabolic flexibility: https://www.levels.com/blog/what-is-metabolic-flexibility-an...

My understanding is that essentially all high-level endurance athletes are just maximizing their simple sugar intake at all times (during exercise) and knowing blood glucose/ketone levels wouldn't change anything about that intake, nor would it have any impact on crashes.

All high level endurance athletes are on high carb diets all the time and are never anywhere near ketosis (unless something has gone very wrong)

Not all. Some runners play around with doing fasted long runs to enhance fat burning adaptations. The jury is still out on if it is advisable to add to a training plan. Some utlra runners have taken to extremes.

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