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.

10 comments:

Moose said...

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

WON'T YOU THINK OF THE CHILDREN?!?

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%.

Arnaldo Abrantes 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.

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