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Portable replacement for a $60k VO2 Max machine

instructables.com

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Re: Portable replacement for a $60k VO2 Max machine

#91

Post by idealmedtech »

762236 wrote: post #13
hourislate wrote: post #5

First comment on page. >My wife is an Ironman as well (Muskoka, Tremblant and Penticton). . She's been using Zwift since last year. Great way to train btw and great idea but. My concern would be a collapsed lung(s) if this wasn't calibrated correctly. To each their own, but stressing your lungs and diaphragm this much isn't a great idea. In a lab they can at least make sure you don't hurt yourself.

How would you get a collapsed lung from using this? And how does its calibration influence whether you get a collapsed lung? This device doesn't interfere with inspiration, and a large breath of air inflates your alveoli.

Questions like this are why people should not be building medical devices at home. Your average athlete interested in this may lack the necessary medical knowledge to understand that a collapsed lung is a possibility when using this device, and cause themselves serious bodily harm.

Re: Portable replacement for a $60k VO2 Max machine

#92

Post by maxwell86 »

nradov wrote: post #60
csours wrote: post #11

Neat! I've been thinking about this lately. If you had accurate CO2 and O2 measurements, you could calculate how many milligrams of fat you are burning during exercise.

This device doesn't appear to contain a CO2 sensor.

It contains a laser CO2 sensor.

Re: Portable replacement for a $60k VO2 Max machine

#94

Post by carbocation »

This is a cool project. The lack of CO2 sensing is a significant limitation. This wouldn’t replace a CPET because of that limitation. I know that’s not what it claims to replace (though the price tag seems to suggest so). But that could be a modification that would have significant value. It would allow you to triangulate your anaerobic threshold, for example.

Re: Portable replacement for a $60k VO2 Max machine

#95

Post by jacquesm »

mikewarot wrote: post #59
jacquesm wrote: post #24

Earlier quoted context omitted.

It is pressurizing on output due to the flow through the device, the same thing causes some underpressure when breathing in. But I doubt it is enough to draw a vacuum strong enough to break adhesion. Still, better safe than sorry, it would be good to read the instruction manual of a professional unit to see what kind of failure modes they have listed there.

I read a lot of stuff back in 2020 because I was going to be coding up controls for an emergency ventilator... you would not believe just how little pressure difference it takes to permanently ruin your lungs... less than 1 PSI if I recall correctly.

You really don't want to over-pressure your lungs with 1 PSI, that's huge for tissue. For a regular party balloon that you blow up the pressure is less than 0.5 psi. But a flow meter in a sports measurement device should be a fraction of that, after all, the back pressure is going to take away effort that should go into providing work.

Re: Portable replacement for a $60k VO2 Max machine

#96

Post by swores »

andreskytt wrote: post #81
dpeck wrote: post #44

Earlier quoted context omitted.

I appreciate the modesty, but talking about completing an Ironman and having the phrase “really wasn't all that fit” anywhere near it is comical. Getting through any one of the stages of an Ironman (or heck even a half of each stage) represents a level of fitness most adults do not have and will never attain.

Not necessarily true, I think. It’s a mental barrier more, than a physical one. Tell someone you ran 100 m in 12 seconds and they go “meh”. Tell them you did a marathon and they go “i could not do that, awesome, how could you etc.” whereas an average person can do a marathon with a years worth of training and never achieve that sprint time. It took for me 21 months of training to go from effectively zero to a half ir…

The person you're replying to spoke of what levels people do and will reach, not can reach.

Just as the ability to learn how to fly planes within a year doesn't change the fact that most people aren't and won't become pilots.

Re: Portable replacement for a $60k VO2 Max machine

#97

Post by aenis »

Karunamon wrote: post #38
hprotagonist wrote: post #37

Earlier quoted context omitted.

do you have experience in the discipline? It doesn’t sound like you do. I have some experience, and i can think of about a half dozen ways cpap machines and hearing aids could cause serious harm as a result of design flaws or lack of QA that would be de rigeur if not for regulatory pressure.

What are some of those ways that are not addressed by regular old (non-medical-specific) electronics/safety regulation? Most of the ways I can think of a CPAP failing would be extremely obvious with equally obvious and relatively low-impact effects (I get a crappy night's sleep or wake up in the middle of the night).

Recent case involving very popular Philips Respironics machines: the foam used for internal insulation was degrading and getting into the stream of air, landing those particles in patients lungs. Huge recall, etc. The kind of problem that testing imposed by regulators can detect.

Incorrect use of CPAP can lead to development of central apnea. (Even APAP machines can be programmed to keep the pressure too high which is long term unhealthy).

With that, I am all for liberalization of the laws. My GP did not prescribe me a CPAP machine despite obvious signs of apnea. "Lose some weight instead" (that despite me having apnea even when I had a BMI of 21).

I never felt as much of a positive difference on my life as when I started using the machine and had my first good night of sleep in decades.

I wish my govt would let me buy an insulin measurement device, but nope, those too are regulated and not available for the general public.

Re: Portable replacement for a $60k VO2 Max machine

#98

Post by texasbigdata »

andreareina wrote: post #67
rct42 wrote: post #58

Earlier quoted context omitted.

Exactly. While the marathon is an endurance event, the intensity when racing is often higher than 65% VO2 max - the "fat max" or point at which fat oxidation peaks. For example, for a 3 hour marathoner (or faster), the intensity would be around 74-84% VO2 max or 80-90% max heart rate. It has also been observed that going on keto reduces your running economy (so you end up running slower for the same effort). As for "…

AIUI 60g/hr is for pure glucose, thanks to co-transport another 50% can be handled as fructose (i.e. 2:1 glucose:fructose ratio)

Not to be an idiot but you're implying 90g just to confirm the math.

Re: Portable replacement for a $60k VO2 Max machine

#99

Post by andreareina »

texasbigdata wrote: post #98
andreareina wrote: post #67

Earlier quoted context omitted.

AIUI 60g/hr is for pure glucose, thanks to co-transport another 50% can be handled as fructose (i.e. 2:1 glucose:fructose ratio)

Not to be an idiot but you're implying 90g just to confirm the math.

Yup

Re: Portable replacement for a $60k VO2 Max machine

#100

Post by trentnix »

vjk800 wrote: post #82
lhl wrote: post #78

Earlier quoted context omitted.

For those interested, Jeff Volek's team published a study in 2016, "Metabolic characteristics of keto-adapted ultra-endurance runners" [1] that compared fax oxidation. One of the "fat adapted" participants Zach Kibbter, an ultra-marathon record holder, posted a personal writeup that included a table of his fat usage at various VO2 Maxes (a ridiculous 98% fat usage at 75% VO2max and 76% even at 84% of VO2max!)[2] [1]…

What would those numbers be for the general population or someone who is slightly fit but not a freak?

At that effort, close to 0. Maybe 20% for someone with great genetics.
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