Bryan Jasker PT, DPT

Here is the link to our MetFlex Index paper. A lactate-based health and fitness assessment. frontiersin.org/journals/physi…

@MarcusMilione It is possible. We are building.

I want to build a continuous blood lactate meter (if its even possible) anyone want to build together

@feelthebyrn1 We've observed acute and substantially declines in lactate clearance capacity during respiratory illnesses. Usually see this impact within a few days lasting a few weeks. Never seen clearance return to baseline spontaneously thereafter. This effect may persist for some.

Lactate Response after Fever Interesting one that's included in next Thursday's article 1⃣Back in covid, I noticed that exposure to a virus would elevate lactate vs power regardless of whether I progressed to illness 2⃣I had also noticed that my lactate would elevate after a febrile illness. Taking these together, whenever I confirm (multiple samples) elevated lactate in my warm-up, I keep it easy that day. I've called off a couple peppy bike workouts using the rule of thumb. Bek's coming off an illness, with fever, so I had him test lactate vs power. 🔴The red is one week after all symptoms cleared. 🟢The green line is two weeks after all symptoms cleared. We took the elevated lactate (red line) as an indication to keep being cautious, even though he felt fine. We wanted to share our experience as a submax test is a simple and low-stress way to check internal stress/metabolic function

@BaptistHealthSF @JonFialkowMD Fun and insightful event with fantastic hosts! Thanks for letting me chat about maintaining metabolic flexibility in aging. Lots more to learn...

The Lifestyle & Longevity Medicine Symposium brought together physicians and experts across disciplines to explore practical, evidence-based approaches to prevention, metabolic health, precision diagnostics, and emerging longevity therapeutics.

Is there a standard of practice to monitor resting lactate levels when dosing metformin? Curious bc anyone I've tested taking metformin had a resting [La] over 2 mmol and typically did not clear with light physical activity. When metformin held I saw normal patterns in lactate levels and clearance.

My wife Jen tells me that my friend @BenBikmanPhD is tweeting on recent evidence indicates that adding metformin to exercise antagonizes the exercise-induced improvement in insulin sensitivity and cardiorespiratory fitness. Here is a paper that backs Ben up pubmed.ncbi.nlm.nih.gov/30548390/ @ProfTimNoakes @grantsnz @nnedpro @AKoutnik

Metabolic Flexibility Metabolic Flexibility refers to how efficiently your body processes energy like carbohydrates and fats. It’s mostly based on supply and demand, what’s available and what you’re doing or (or not doing). Losing flexibility (not talking about your hamstrings) is related to changes in metabolic health, typically not the good kind. It can be measured by a few methods, for example, with a mask measuring the gases you are breathing (RER) or by seeing how glucose and insulin respond over time to a sugary drink (OGTT). OVAL measures metabolic flexibility during an exercise test by sampling lactate as the test increases in intensity. From the test results, we describe your status of your metabolic flexibility as the MetFlex Index, offering direct insight into your metabolic operating system. Below is a comprehensive review on Metabolic Flexibility by Goodpaster and Sparks. pubmed.ncbi.nlm.nih.gov/28467922/

@Dan_Wyke @katiamek Submax protocols to just 1st lactate threshold are sufficient in my experience for diagnostics

@katiamek Yes, it's clearly risky. We need safer diagnostic biomarkers for use in clinical settings.

"This research provides molecular validation for what ME/CFS patients have long known—that their bodies respond abnormally to exertion. The recovery phase in ME/CFS is characterized by prolonged, maladaptive molecular responses rather than a healthy return to baseline." #MECFS

@JohnGoldman Yes. And pretty much global at this point.

We have a movement crisis in America.

In her NYT article, “What Is ‘Metabolic Health,’ and Why Does It Matter?”, Author Nina Agrawal discusses dysfunctional metabolism and its impact on health and disease in the U.S. Often, conversations around the terms ‘metabolism’ or ‘metabolic’ are framed around nutrition, calories, weight, and obesity. As Nina mentions in her article, movement also plays a role in preventative strategies, noting the  public health recommendations of 150 minutes a week of moderate aerobic activity, alongside strength or resistance training.  General recommendations are helpful for generating awareness but aren’t necessarily successful at the individual level since each of us differs in form and function and improving our metabolic health is not a one-size-fits-all solution.  Our work at OVAL has been to create a science based, personalized movement program to reboot your metabolic operating system. Improving your body’s ability to manage stress and energy is key to restoring sustainable health. Over the next few months I will provide explanations for how OVAL measures and manages your metabolic health through movement. Stay tuned… nytimes.com/2026/01/16/wel…

@JohnGoldman You have visual comps or graph for lactate test 1 vs this most recent one? Great work John!

#ProjectUnreasonable Update - LACTATE TEST RESULTS In Alan's words, "Well, holy crap! I didn’t expect to see that…" and "I can’t overstate how good the fat-burning numbers are. I typically see these sorts of numbers in 2 people… Die-hard keto athletes World Champion ultra athletes. To have these numbers already is a great launch point!" To say that surprised me is an understatement. I was carrying a sense of failure because I didn't push myself as far as I could have in the 40 minute test. I bailed out at around 165 BPM. But, the goal wasn't to get a max test, but to get this lactate curve and fat ox numbers, which we did successfully. What this means for me long term is that I have the fat burning engine most normal people never achieve and that elite athletes aspire to. So that's a good sign! In the short term, this means we lower my HR caps on easy and long runs. Which...is counter intuitive to me. We do this because my stroke volume has improved and I can achieve the goals we want with lower stress. So because I'm in the hands of a true expert like Alan, that means we're being efficient and protecting me for the long run by only doing what is necessary...and not doing what I feel like I should be doing which is running harder lol. Areas for improvement: - More work on lifting cadence during the runs to see if we can improve those economy numbers a little in the next test. Would like to get these to <210 ml/kg/km by the time the race rolls around. So I'll focus on cadence with my in person running coach. - Can gradually eek up carbs/cals a little. Fat ox is already crazy strong and Alan wants to see an additional stage/a higher max RER in the next test. Will check in with RD to adjust appropriately. VO2MAX numbers: - VO2peak = 4.6 L/min = 46.2 ml/kg/min at current weight. Scaled to target race weight = 54 ml/kg/min, and again, considering we were missing a little oomph at the end, likely +10% on that. So maybe estimate current vo2max at 50ish. Other observations: - Quite a balanced lactate curve. First threshold (AeT) ~60% max. Second threshold (AnT) ~85% max. First HR deflection at ~120 bpm indicating cardiovascular benefit (improved stroke volume) from training at this point, i.e. don’t hesitate to go Eazzzzy esp with cross-training. - Relatively flat after that first 0.4 rise, i.e. a plateau in that 130-140bpm range where I have been spending a lot of time. Indicating well-conditioned fibers in this range. Quoting Alan again "Overall, a great test! That metabolic fitness that you’ve built is going to have a huge impact on both training tolerance and race performance moving forward!" So all in all we discovered some amazing things about my metabolic capacity, I learned something about my effort levels, and the stage is set for efficient load management and the next 40+ weeks of base training. Good day at the lab!

@MVAitor Rabinowitz lab doing solid work on metabolic flux

Lactate, a metabolite with big capacities to regulate its own metabolism. Why has lactate this “metabolic power”? Check the following paper titled “Lactate homeostasis is maintained through regulation of glycolysis and lipolysis.” Well done to authors! sciencedirect.com/science/articl…

@johngoldman Thanks John. Appreciate you sharing the link to our paper.

Interesting approach to assessing metabolic flexibility and its relationship to various health markers.

@SrihariNaiduMD @SandeepNathanMD @Babar_Basir @agtruesdell @SarasVallabhMD @adityadoc1 @SCAI @CRT_meeting @davebaran @thiele_holger @nymedcollege Would your profession find utility in a continuous lactate wearable that samples every 30 seconds for 2 weeks?

SCAI DLC INITIATIVE PDF now live! Thanks for spreading the word! Link: jscai.org/action/showPdf…

@hrv_tokyo We are currently in development

A friend of mine who is a coach at the World Athletics Championships is looking for a device that can continuously measure lactate levels. If anyone knows of such a device, please let me know.

@Alan_Couzens "This is the way" - Midichlorians

Your overall health is strongly tied to the health of your mitochondria (the energy factories of the cell)🏭 One of the best ways to assess how "cleanly" your factories are operating is lactate🩸 Healthy mitochondria=⬇️lactate Are your factories polluting your whole system?

@StuartBlitz Try a @portilloshotdog double cheeseburger. Best I've had in a while.

Heard this was the best burger in America

Incase you missed the inaugural vLamax conference. Please find all of the recorded talks on YouTube. Please share wide and far and enjoy the really insightful talks! Thank you again to all presenters! #vlamax #conference #physiology @vlamaxconference2025?si=ZGLOxvJJFH6tEN_I" target="_blank" rel="nofollow noopener">youtube.com/@vlamaxconfere…

@Jason Wearables are still point solutions for health metrics like health care is for disease metrics. Need a systems biology approach to understand foundational health. OVAL solves this. We are a combined diagnostic (the MetFlex Index) and therapeutic (individualized programs). .

Quantified self/health-focused folks: Tell me about your stack of services / partners / products / protocols / coverage holes

@MitoPsychoBio @calleymeans I believe we are close. frontiersin.org/journals/physi…

One of the problem is that our *health* experts are actually *disease* experts We don’t have a single quantitative measure of health, nor do we have a first-principles understanding of what health is We need a new science: Healing Science @calleymeans