Pulse oximiter?

why would anyone care what their oxygenation in the ear lobe or finger tip is whilst working out?  If he is upright and mentating he is oxygenated.

no. no benefit

x3 on not useful.

Your pulse ox isn't going to drop substantially even with the most intense exercise. It's a myth that any healthy person has "oxygen deprivation" or anything of the sort while training or racing.

As an ER nurse I can attest that unless there is an underlying medical reason, there would be no benefit.

High peaks = cold = won't work.
Diving = water = won't work. (Unconsciousness = can't read pulse oximeter = waste of time. )

Waste of time and money.

Interesting if the bike part was at high altitude.



You could sneak a bottle of oxygen in your camelback.  You could monitor your oxygen with the pulse ox and then turn on the oxygen at a critical threshold.

Otherwise I agree with the other posters that it would not be needed.  I'm thinking they don't make very good heart monitors.  I tried one on a treadmill once.  It was one that went on your ear.  It kept falling off and I almost stepped on it.  It seemed to stop registering around 120 beats per minute.

For mountaineering, they are useful.  You aren't  trying to read it when you are buried in the snow, but in the tent, which is usually above freezing. They are sometimes used to monitor acclimatization for safety in climbing (like here).

For diving, they are used on the boat/shore, not underwater.  They may have a role when people are using either exotic gas mixes (such as heliox) or closed circuit rebreathers, where there is a risk of getting too little O2. Or in the event of needing to provide CPR, to determine if there is adequate oxygenation going on (link)

So I stand by my claims.  Having said that, even in those situations, I doubt if they are going to be routinely useful in day to day use for most people, especially in a diving capacity. In the situation I was present where a diver perished, we had to perform CPR until the coast guard arrived, but I doubt if being able to document the persistent lack of oxygenation wouold have allowed us to stop earlier.

No. Zero benefit.

Not necessarily true... It's true that beyond LT the body isn't getting enough oxygen, but pulse ox is a measure of pulmonary gas exchange--Even if your pulse ox is 100% during exercise, it's oxygen EXTRACTION, not oxygen absorption/delivery, that's causing the deficit. If you really want to see that, just let me drop a central line in you and connect you to a continuous mixed venous O2 sat monitor while you exercise.

Everyone does have a VO2Max, i.e. maximal level of oxygen consumption, but it's not something that changes during a workout, and again has nothing to do with O2 Sat.


Edited by DrPete 2009-09-05 9:46 AM

Right, which is why a pulse ox is useless since it measures peripheral oxygenation. The rate limiting step is at the cellular level.

I'm not quite sure what you're disagreeing with.

The statement that there's NO oxygen deprivation in a healthy, trained athlete. There is, just not at the arterial blood level. Splitting hairs, I know.

Thanks for the replies.  I am Mrs. Tri365's husband, and I do hike and climb at high altitudes, generally in the Sierra Nevada, where the highest elevation tops out at ~14,500 feet.  I have had issues in the past in which I have been troubled by seeming altitude sickness, but noted that my heartrate was not doing what I thought it should be doing, given the leel of exertion that I was doing.  Bear in mind that I am not trail-running, just trying to go at a consistent pace to get to my destination in a reasonable period of time. <br><br>

I noticed that my sypmtoms came on gradually, and by the time I realized that I should have paused at a lower eelvation (say 11,000 feet,) I had already hked up to 12,000 feet, resulting in my being light-headed and sluggish.  I do try to acclimate properly, and I do stay well-hydrated.  I was wondeing whether or not checking my readings on a pulse oximeter would have given me an advance indication that I needed to stay at the lower altitude overnight before going onward. <br><br>

The feedback from my own body was such that my heart rate was not racing, but I was getting ot of breath right away.  I would sit and rest, and 60 seconds later I would feel energetic, I'd get up, and 1-2 minutes later find myself gasping again.  Even taking a few a few seconds to drink water was enough to put me out of breath.  Very frustrating.<br><br>

In the end, I did turn around and reduce my elevation, and I am familiar with the symptoms of HAPE and HACE.  I was just curous about if a pulse oximeter would have been at all useful up there.  I didn't think it would have any application down here at ~sea level.<br><br>

Thanks all!

^^^ The fact that you knew enough about the effects of altitude make it clear that there's nothing the pulse ox would've told you that would've made it worthwhile. Yes, it would've read low, and the answer was to go to a lower altitude. Seems you didn't need the device to tell you that.

Errr, there is none. There is ample oxygen. The rate limiting step is our ability to use it on the cellular level.

We're battling semantics here, but at the cellular level it's the inability to extract enough oxygen to support aerobic metabolism. Just because there's enough around doesn't mean the cells have all the oxygen they need. If what you're saying is true, then no healthy athlete anywhere should ever be using anaerobic metabolism.

Cells don't care if you're not inhaling enough oxygen, not getting it into the blood, or not extracting enough. It's still tissue hypoxia.

Edited by DrPete 2009-09-05 11:35 AM

At altitude the pulse-ox would also likely not pick up very well due to temperature variation - and again I highly DOUBT your pulse ox drops much even though there is less oxygen at that level

you would have to go up to Everest, Denali etc to really see a pulse ox drop.

your symptoms should be your guide, you should work on hydration and you could take a carbonic anhydrase inhibitor

Not so much.

In fact, there's enough of a drop that the "normal" SpO2 for children at altitude is 87%. Granted, they adapt over time, but in unacclimated subjects SpO2 does drop at altitude. This has been reported in pilots who fly in unpressurized aircraft above 6000 feet. SpO2 of <86% is also predictive for development of AMS, and that occurs at MUCH lower altitudes than Everest/Denali.

Edited by DrPete 2009-09-05 11:52 AM

For those who will accuse me of pulling numbers out of thin air (hehehe), this comes from Auerbach's Wilderness medicine, 5th ed.

POPULATION	ALTITUDE (m)	ALTITUDE (ft)	PB (mm Hg)	Pao2 (mm Hg)	Sao2 (%)	Paco2 (mm Hg)
Altitude residents[*]	1,646	5,400	630	73.0 (65.0–83.0)	95.1 (93.0–97.0)	35.6 (30.7–41.8)
Acute exposure[†]	2,810	9,200	543	60.0 (47.4–73.6)	91.0 (86.6–95.2)	33.9 (31.3–36.5)
	3,660	12,020	489	47.6 (42.2–53.0)	84.5 (80.5–89.0)	29.5 (23.5–34.3)
	4,700	15,440	429	44.6 (36.4–47.5)	78.0 (70.8–85.0)	27.1 (22.9–34.0)
	5,340	17,500	401	43.1 (37.6–50.4)	76.2 (65.4–81.6)	25.7 (21.7–29.7)
	6,140	20,140	356	35.0 (26.9–40.1)	65.6 (55.5–73.0)	22.0 (19.2–24.8)
Chronic exposure during Operation Everest II[‡]	6,500	21,325	346	41.1 ± 3.3	75.2 ± 6	20 ± 2.8
	7,000	22,966	324	—	—	—
	8,000	26,247	284	36.6 ± 2.2	67.8 ± 5	12.5 ± 1.1
	8,848	29,029	253	30.3 ± 2.1	58 ± 4.5	11.2 ± 1.7
Acclimatized subjects studied during acute exposure to the simulated summit of Everest[§]	8,848	29,029	253	30.6 ± 1.4	—	11.9 ± 1.4

Data are mean values and (range) or ±SD, where available. All values are for subjects of age 20 to 40 years who were acclimatizing well.

funny in his lectures the two times I have attended the wilderness medicine conference he made a point that  pulse ox does NOT drop.  But even in the table you show, you have to get between 12-15,000 feet to see a drop below 90%

That's Adams/Whitney/Rainier country, though--altitudes easily reached in the continental US on mountains or at some ski resorts.

Edited by DrPete 2009-09-05 12:16 PM

Inability to extract oxygen is not the same as "oxygen deprivation" which was the original quote. It's the inability to use the oxygen which is plentiful. You've said as much yourself.

Yes, it's splitting hairs.

Swimming endless laps, riding 100's of miles and running till our toe nails fall off is a normal land activity?