Thursday, February 7, 2013

Why supplemental oxygen is not considered a performance-enhancing drug

You often see a football player on the sidelines breathing oxygen after running a long distance or having worked hard during a long series of plays.

Have you ever wondered if it works? Does breathing a high concentration of oxygen help an athlete recover from exertion faster?

The answer is a resounding “No,” and here’s why.

In healthy people, such as college and professional football players, nearly all of the oxygen in the blood is carried by hemoglobin. Only a very small percentage is dissolved in blood. Saturation defines the oxygen that is attached to hemoglobin and partial pressure of oxygen is that which is dissolved in blood.

Definitions: SaO2 = arterial oxygen saturation, Hb = hemoglobin, 1.34 mL is the amount of oxygen a fully saturated gram of hemoglobin can carry, Pa02 = partial pressure of oxygen or the amount of oxygen dissolved in blood

If an athlete has a normal Hb level of 15 gm, a SaO2 of 100% and a PaO2 of 100 mmHg, the formula used to calculate his blood oxygen content is

[Hb X 1.34 X (SaO2/100)] + 0.003 X PaO2 or
[15 X 1.34 X 100/100] + 0.003 X 100
20.1 + 0.3 = 20.4 mL/100 mL of blood

So, only about 1.5% of the oxygen content of blood is dissolved.

If an athlete raises his PaO2 to 400 mmHg by breathing pure oxygen the calculation is

[Hb X 1.34 X (SaO2/100)] + 0.003 X PaO2 or
[15 X 1.34 X 100/100] + 0.003 X 400
20.1 + 1.2 = 21.3 mL/100 mL of blood

Even at a PaO2 of 400 mmHg, only 5.6% of the oxygen content of blood is dissolved. Note that hemoglobin cannot be more than 100% saturated with oxygen.

Very soon after the athlete stops breathing the pure oxygen, its minimal effect disappears. It’s simply not enough to affect recovery or performance.

Possibly because the basic science is well-understood, there have not been too many papers on this subject.

Here’s one from JAMA that looked at 12 soccer players given 100% oxygen or placebo after exertion. Then they had to exercise again. “The administration of enriched oxygen during the recovery period had no effect on plasma lactate levels [an objective measure of recovery] or on performance during the second period of exercise. The subjects were unable to identify which gas they received.”

A similar study of 13 athletes from Medicine & Science in Sports & Exercise concluded “These findings offer no support for the use of supplemental oxygen in athletic events requiring short intervals of submaximal or maximal exertion.”

Another from the European Journal of Applied Physiology found that giving athletes supplemental oxygen during the recovery periods of interval-based exercise improves the recovery time of SpO2 [equivalent to SaO2] but did not improve post-exercise markers of reactive oxygen species or inflammatory responses because the improvement in saturation was clinically insignificant.

The situation is explained in simple terms in an excerpt from the book Exercise Physiology: Integrating Theory and Application. It concludes that supplemental oxygen may have a placebo effect, but there is “no real physiologic benefit.”

If you Google “supplemental oxygen and athletes,” you will find a number of websites touting the supposed benefits of inhaled oxygen. They are almost all supported by companies that sell oxygen.

Bottom line: Supplemental oxygen is not considered a performance-enhancing drug because it doesn’t work.

Thanks to  Dr. Joel Topf ( ) for suggesting this topic.


Moose said...

Ban the oxygen! It's as dangerous as dihydrogen monoxide!


artiger said...

Yeah, but it looks cool

Anonymous said...

Or how about "oxygenated water". This was water allegedly "enriched" with extra dissolved O2.

During a short lived fad about 10 years ago, companies were selling bottles of the stuff at about 5 times the cost of regular bottled water.

Skeptical Scalpel said...

Yes, oxygenated water. Another bit of nonsense. Thanks.

Libby said...

I used something from a Homeopath that was 'oxygenated', my RMT laughed at it but the other stuff in it worked in reducing my bruising from the nasty (really nasty) sprain I had. Maybe the oxygen was to cash in on that fad with putting air into drinking water.

Skeptical Scalpel said...

Maybe it was going to get better regardless of what you did.

RuggerMD said...

Oh the O2 on the NFL field.
Hence, my name, I played rugby for 17 yrs and we go 80 minutes with a five minute break.
Those pros in the NFL go 7 seconds then need a hit of oxygen.
Always drove me crazy.

What irritates me even more is every time the respiratory therapist calls me to tell me my ventilated patients pO2 is 54 and wants to turn up the FiO2, despite the sats being 99%
Despite my thousands of face to face re-education attempts to explain the delivery of oxygen equation and how useless dissolved (or partial pressure thereof ) oxygen is in making clinical decisions, I still get asked to up the oxygen daily.
What irks me even more is when my partners turn it up!

Here's my rule: keep the FiO2 as low as possible to keep oxygen sats above 91% or so. When the patients lungs have a little problem, like plugging or atelectasis, they will desat, therefore it is time for some resp therapy.
If you keep the FiO2 really high you will only mask little problems, and by the time the patient desats, they are in real trouble.
It's a lesson all should learn and use, IMHO.

Skeptical Scalpel said...

Rugger, I agree with your way of managing oxygen although I haven't seen many patients with PaO2s of 54 and sats of 99%.

Unknown said...

So why too much oxygen can be harmful in a well train athlete, if he already use all the O2 that he can? Can a football player well trained, with 15gm of Hb and 100% SatO2 use oxygen for 2-3hr after a hard train to recover from lactic acid, with any problem?

Skeptical Scalpel said...

Arnaldo, thank you for commenting. I didn't say using oxygen was harmful. I said it didn't work to improve performance. An athlete can breath 100% oxygen for several hours without any harm. It is a waste of time and oxygen.

To my knowledge, making the PaO2 higher than normal has not been shown to clear lactic acid any faster than breathing room air.

Anonymous said...

What about supplementing during exercise?

Skeptical Scalpel said...

Anon, that's a good question, but it wouldn't help. For the same reason it does not speed recovery after exercise, using supplemental oxygen during exercise would simply increase the PaO2 which is the minor component of oxygen transport in an athlete who is not anemic.

Anonymous said...

what is your oppinion about supplemental oxygen immediately after alpine dh ski race (duration cca 2 min) at altitude 3500m, finish 2700m beaver creek CO and your opinion about supp oxy after few hours for regeneration purposes at 2500 m (vail),

Skeptical Scalpel said...

The SaO2 at 2500 meters would still be about 90%. A trained athlete probably would not need supplemental oxygen. There would also be no need to breath pure oxygen for a few hours. Within a couple of minutes, the SaO2 would be 100% which is as high as it can go. Here's a link which has a chart showing the Pa02 and SaO2 at various altitudes.

Unknown said...

How do Pro athletes medically qualify for oxygen therapy? The criteria for prescription is etched in stone. It is hard for me to believe that half the players in the NFL qualify for O2 therapy.

LL said...


I don't disagree with your analysis and it is interesting thanks. But if it doesn't help recovery at all why is it that the NFL players use it in the first place? Does it help them get their 'breath' back faster?

Skeptical Scalpel said...

I have no idea why NFL players use oxygen. I think it may have a placebo effect. They see others using it and think it must be worth using themselves. It does not help them get their breath back faster for the reasons explained in the post.

Anonymous said...

Does pure oxygen at a controlled level help burning fat cells ? What if going through a 30 minutes cardio everyday and during this time would it actually help or it would be insignificant or even lethal ?

Skeptical Scalpel said...

I'm not an expert on burning fat cells, but I doubt that excess oxygen would help. Again for the reasons explained in the post, adding oxygen to inspired air has very little effect on the amount of oxygen delivered to the tissues of normal individuals such as those who can do 30 minutes of cardio. It would not be lethal either.

Anonymous said...

Why do Hyperbaric Chambers work then?

Skeptical Scalpel said...

What illness or condition besides carbon monoxide inhalation do hyperbaric chambers work for?

Unknown said...

Last week my laboratory spang for an add-on to our first aid training- O2 delivery. We were told again and again that administering O2 in most any situation would not hurt (which I agree with). However the course provider did not appreciate/understand my comments on partial pressure or dissolved O2 in the blood which I remembered from my physiology classes 20 years ago. My comments were driven from the hypothetical situation when a victim in respiratory distress refuses to wear the O2 mask. Aside from the ability to manually assist with respiration by way of a bag, what are your thoughs on insisting that the victim recieve O2?

Skeptical Scalpel said...

In recent years the thinking that every sick or injured patient should receive oxygen has changed.

Too much of anything, including oxygen, is not always good.

Here are a few links that explain:,,,

Anonymous said...

What about breathing pure oxygen during a workout, like while on a treadmill?

Skeptical Scalpel said...

It would not help. In a normal person even on a treadmill, the saturation of oxygen in hemoglobin is 98-100%. Increasing the partial pressure of oxygen dissolved in blood would have very little effect on the total oxygen delivery to the tissues.

Autumn said...

I know this is a tangent to the original post, In VT hyperbaric oxygen "clinics" seem to have sprouted. THe claim is that they help patients with degenerative neuro conditions like parkinson's disease. It pings my woo radar, I know they use it for some wound healing and for CO poisoning but is my woo-dar on track?

Skeptical Scalpel said...

Autumn, yes you are on track. Here are two posts I've written about hyperbaric oxygen. I hope you find them useful. and

Autumn said...

Thanks! Color me unsurprised.

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