Many athletes inhale pure oxygen after exercise in an attempt to

Question

Many athletes inhale pure oxygen after exercise in an attempt to increase muscular re-absorption of oxygen. Measured continuously after exercise, however, the blood lactate levels of athletes who inhale pure oxygen are practically identical, on average, to those of athletes who breathe normal air. The lower the blood lactate level is, the higher the muscular re-absorption of oxygen is.

If the statements above are all true, they most strongly support which of the following conclusions?

(A) Athletes’ muscular re-absorption of oxygen is not increased when they inhale pure oxygen instead of normal air. 
(B) High blood lactate levels cannot be reduced. 
(C) Blood lactate levels are a poor measure of oxygen re-absorption by muscles. 
(D) The amount of oxygen reabsorbed by an athlete’s muscles always remains constant. 
(E) The inhaling of pure oxygen has no legitimate role in athletics.

OG 2017 New Question
ID - CR01112

Inhaling Pure Oxygen

Step 1: Identify the Question

The phrasing statements...support which of the following conclusions in the question stem indicates that this is an  Inference  question.

Step 2: Deconstruct the Argument

Many athletes inhale O to increase MR

BUT: O athletes vs non O athletes: same lactate

low lactate = high MR

Because this is an Inference question, the argument itself will not contain a conclusion. Instead, it states a series of related facts about the practice of inhaling pure oxygen after exercise. Many athletes believe that it increases muscular reabsorption. However, there is some evidence to the contrary: lactate levels reflect muscular reabsorption, and lactate levels do not change in athletes who inhale pure oxygen.

Step 3: Pause and State the Goal

In an Inference question, the right answer will be a statement you can prove using solely the information given in the argument.

Step 4: Work from Wrong to Right

(A) CORRECT . The last sentence of the argument relates muscular reabsorption of oxygen and lactate levels. Athletes with lower lactate levels have higher muscular reabsorption of oxygen. However, athletes who inhale pure oxygen do not have lower lactate levels. It stands to reason that these athletes also do not have higher muscular reabsorption.

(B) According to the argument, inhaling pure oxygen after exercise does not decrease blood lactate levels in athletes. However, it’s too much of a stretch to say that blood lactate levels cannot be reduced at all. It’s possible that they could be reduced through some other means, or in some other population.

(C) There’s no way to tell whether this is the case, using the information provided in the argument. It’s possible that the athletes’ muscular reabsorption of oxygen actually is increased, and their lactate only fails to decrease because blood lactate levels are a poor measure. However, it’s also possible that blood lactate is a good way to measure muscular reabsorption, and these athletes’ muscular reabsorption is not increasing—that is, the evidence from the lactate levels might be correct.

(D) The argument shows that athletes who inhale pure oxygen after exercise do not necessarily increase their muscular reabsorption of oxygen. However, the amount of oxygen reabsorbed by their muscles might not always remain constant. It’s possible that reabsorption changes for other reasons, or even changes at random.

(E) This is a real-world inference, but not an appropriate GMAT inference. Most likely, the person making the argument did so in order to argue against using pure oxygen in athletics. However, this can’t be proven using only what is stated in the argument. The argument only provides evidence that pure oxygen does not aid muscular reabsorbtion. Pure oxygen could have some other legitimate role.

mikemcgarry · Accepted Answer

Dear AbdurRakib , I'm happy to respond. :-)

The last sentence is the most important, a good place to start. Low blood lactate level --> high muscular re-absorption of oxygen There's a direct numerical link between those two. Now, look at the second sentence: if athletes who use the pure oxygen and those who don't have more or less the same blood lactate levels, this means they must have more or less then same muscular re-absorption of oxygen. With this mind, look at the first sentence: inhaling the pure oxygen doesn't appear to make any difference. That's the conclusion, and this is exactly what (A) says. Choice (A) is the best answer. (B) is not supported by what is said and seems unreasonable. (C) directly contradicts the last sentence (D) is not clear: it could be true, or it may not be (E) is a far-flung judgment, way out of scope. BTW, outside of this question, my understanding of biology is that (B) & (D) are patently false. Does all this make sense? Mike :-)

GMATRockstar · Answer

https://www.youtube.com/watch?v=Ef0WSljbQk0

Skywalker18 · Answer

Many athletes inhale pure oxygen after exercise in an attempt to increase muscular re-absorption of oxygen. Measured continuously after exercise, however, the blood lactate levels of athletes who inhale pure oxygen are practically identical, on average, to those of athletes who breathe normal air. The lower the blood lactate level is, the higher the muscular re-absorption of oxygen is.

Premises - Blood lactate levels of athletes who inhale pure oxygen are practically identical, on average, to those of athletes who breathe normal air->Pure oxygen has no effect on Blood lactate levels of athletes
- The lower the blood lactate level is, the higher the muscular re-absorption of oxygen is.-> blood lactate level and muscular re-absorption of oxygen are inversely proportional .

Inference -

A) Athletes’ muscular re-absorption of oxygen is not increased when they inhale pure oxygen instead of normal air. Correct - Can be inferred by combining the premises 
B) High blood lactate levels cannot be reduced. Irrelevant -
C) Blood lactate levels are a poor measure of oxygen re-absorption by muscles. Contradicts the last statement in the argument
D) The amount of oxygen reabsorbed by an athlete’s muscles always remains constant. - May be true but we can't infer that this must be true
E) The inhaling of pure oxygen has no legitimate role in athletics. Out of Scope 
Answer A

dixitraghav · Answer

I have one doubt. Low blood lactate level implies high muscular re-absorption of oxygen, CONSIDERING EVERYTHING ELSE REMAINS SAME, right?

How do we know that Pure oxygen does not impact some other parameter, resulting in higher muscular re-absorption of oxygen? It is certainly possible.

Hence, how can we conclude: Athletes’ muscular reabsorption of oxygen is  not  increased when they inhale pure oxygen instead of normal air.

It is possible that pure oxygen impacts X, which does not necessarily impact blood lactate level. However, lets say that X does impact WBC count in the blood and higher WBC count leads to higher muscular reabsorption.

mikemcgarry · Answer

Dear dixitraghav , I'm happy to respond. :-)

My friend, don't confuse correlation for causality . All we are saying here is that low blood lactate level is correlated with high muscular re-absorption of oxygen: where we find one, we find the other. Because blood lactate level is very easy to measure, it turns out to be a good indicator for muscular re-absorption of oxygen, which is hard to measure directly. This does NOT mean that low blood lactate level causes high muscular re-absorption of oxygen. We don't know what the mechanism of causality is, whether one causes the other or both are caused by something else, and we don't need to know. All we need to know is the correlation: no matter what is causing what, we know for a fact that low blood lactate levels are always found with high muscular re-absorption of oxygen. Now, we don't know, but it certainly seems reasonable to predict that pure oxygen might lead to higher muscular re-absorption of oxygen. If an athlete breathed pure oxygen, we might predict that, after breathing this, the athlete's muscular re-absorption of oxygen would be higher. If this were higher, then it definitely would be true that blood lactate level would be lower, because that's the nature of the correlation. The fact blood lactate levels are not measured to be lower means this prediction is not supported by experimental data. Again, correlation says absolutely nothing about what is causing what: it simply tells us what two things are typically found together. Does all this make sense? Mike :-)

lohitkc · Answer

Hi Mike, the argument says that the blood lactate level of the athletes are identical,  on average . That means for some athletes blood lactate level can increase, while for others it can decrease. Now, if we see the option (A), it says that " Athletes’ muscular re-absorption of oxygen is not increased ......", isn't this a very strong conclusion for the argument? It can still decrease for some and remain average for the complete group. Can you please explain my reasoning? Thank you.

BillyZ · Answer

Inhaling Pure Oxygen

Step 1: Identify the Question

The phrasing statements…support which of the following conclusions in the question stem indicates that this is an Inference question.

Step 2: Deconstruct the Argument

Many athletes inhale O to increase MR
BUT: O athletes vs non O athletes: same lactate
low lactate = high MR

Because this is an  Inference  question, the argument itself will not contain a conclusion. Instead, it states a series of related facts about the practice of inhaling pure oxygen after exercise. Many athletes believe that it increases muscular reabsorption. However, there is some evidence to the contrary: lactate levels reflect muscular reabsorption, and lactate levels do not change in athletes who inhale pure oxygen.

Step 3: Pause and State the Goal

In an  Inference  question, the right answer will be a statement you can prove using  solely the information given in the argument .

Step 4: Work from Wrong to Right

(A)  CORRECT . The last sentence of the argument relates muscular reabsorption of oxygen and lactate levels. Athletes with lower lactate levels have higher muscular reabsorption of oxygen. However, athletes who inhale pure oxygen do not have lower lactate levels. It stands to reason that these athletes also do not have higher muscular reabsorption.
(B) According to the argument, inhaling pure oxygen after exercise does not decrease blood lactate levels in athletes. However, it’s too much of a stretch to say that blood lactate levels cannot be reduced at all. It’s possible that they could be reduced through some other means, or in some other population. 
(C) There’s no way to tell whether this is the case, using the information provided in the argument. It’s possible that the athletes’ muscular reabsorption of oxygen actually is increased, and their lactate only fails to decrease because blood lactate levels are a poor measure. However, it’s also possible that blood lactate is a good way to measure muscular reabsorption, and these athletes’ muscular reabsorption is not increasing—that is, the evidence from the lactate levels might be correct.  
(D) The argument shows that athletes who inhale pure oxygen after exercise do not necessarily increase their muscular reabsorption of oxygen. However, the amount of oxygen reabsorbed by their muscles might not always remain constant. It’s possible that reabsorption changes for other reasons, or even changes at random.
(E) This is a real-world inference, but not an appropriate GMAT inference. Most likely, the person making the argument did so in order to argue against using pure oxygen in athletics. However, this can’t be proven using only what is stated in the argument. The argument only provides evidence that pure oxygen does not aid muscular reabsorbtion. Pure oxygen could have some other legitimate role.

Squib17 · Answer

I too had the same doubt while solving the question.

But then went with Option A, because this is the only option that can be most strongly concluded from the information given to us. Would be happy if someone can help understand if my thinking is correct.

mikemcgarry · Answer

Dear Squib17 , I'm happy to respond.

What you need to understand is that for all natural traits of the human body, there are natural variations. Whether we are talking about running speed or visual ability or cardiovascular endurance or the " muscular re-absorption of oxygen ," there are going to be wide variations when we look at different human beings. This is always always always the case. Thus, the athletes who inhale pure oxygen have some natural variation in the muscular re-absorption of oxygen ," and hence, some natural variation in " blood lactate levels ." If we took 50 different athletes who inhaled pure oxygen, we probably would get 50 different readings for " blood lactate levels ," probably roughly distributed on a normal distribution, and we would take the average, the mean, of this set. Similarly, the athletes who just breathe ordinary air also have some natural variation in the muscular re-absorption of oxygen ," and hence, some natural variation in " blood lactate levels ." If we took 50 different athletes who breathed ordinary air, we also would get 50 different readings for " blood lactate levels ," again probably roughly distributed on a normal distribution, and again we would take the average, the mean, of this set. The argument is telling us that these two means are about equal. Sure, there are some highs and lows in both sets, because there's always natural human variation, but that doesn't allow us to conclude that there's any special effect of inhaling pure oxygen. In fact, if the means of the two sets are just about equal, then we have a statistical basis to reject the conclusion that inhaling pure oxygen increases the muscular re-absorption of oxygen. Thus (A) is the statistically sound conclusion to draw. Does all this make sense? Mike

HimanshuW11 · Answer

The argument cites couple of facts:
1. Many athletes inhale pure oxygen after exercise in an attempt to increase muscular re-absorption of oxygen. 
2. Measured continuously after exercise, however, the blood lactate levels of athletes who inhale pure oxygen are practically identical, on average, to those of athletes who breathe normal air.
3. The lower the blood lactate level is, the higher the muscular re-absorption of oxygen is

Inference

This options is derived form the point two in the facts cited by the argument. Let's keep this and see the next options.
 
Cannot is too extreme hence red flag this option. The argument mentions nothing about the high lactate levels. So this option goes out.
 
Poor????? The argument mentions this no where.
 
Always, makes me red flag this option as well. The argument mentions about muscular reabsorption of oxygen in 2 different scenarios. See point 1 and 3 above. Hence this answer option can't be inferred.
 
NO=Red Flag. No where mentioned the role. All we know is that Inhaling pure oxygen increase muscular re-absorption of oxygen. What does muscular reabsorption does, we don't know. Hence this answer option can't be inferred.
Answer:A

Sarjaria84 · Answer

Hi  AjiteshArun   VeritasKarishma   mikemcgarry

I marked option D as the answer and now I understand why it is incorrect. The argument is talking about a specific scenario 'after exercise' and option 'D' generalizes it to 'always'.

My question is, if, with no option 'A' present, option 'D' would have stated that,

- The amount of oxygen reabsorbed by an athlete’s muscles remains constant after exercise.

Is the above statement absolutely (inferred) true based on the statements given in the argument?

Thanks
Saurabh

KarishmaB · Answer

No, all we can say is that inhaling pure oxygen instead of normal air doesn't increase amount of oxygen reabsorbed by an athlete’s muscles. Will the amount of oxygen reabsorbed remain constant in all situations, we don't know. Perhaps doing stretches or taking some medicine could increase the amount of oxygen reabsorbed.

MartyTargetTestPrep · Answer

Choice (A) is not fully supported by what the passage says.

It could be that blood lactate levels are just one factor affecting muscular re-absorption of oxygen, and what the passage says does not clearly indicate that there is an absolute and constant relationship between blood lactate levels and muscular re-absorption of oxygen that is not affected by other factors. So, choice (A) is not fully supported. It is merely the best supported, and not that well supported.

willacethis · Answer

Dear experts,

As per my understanding, an inference is something that is 100% true after assuming that facts mentioned in the argument are true. Now, considering this question an inference question, how are we ABSOLUTELY SURE that athletes' muscular re-absorbtion of oxygen is not increased as mentioned in option A.

For instance, can't there be a case that athletes who inhaled pure oxygen initially had a lower muscular ability to re-absorb oxygen (than other athletes) before they inhaled pure oxygen? Thus, by inhaling pure oxygen, their increased blood lactate level might have turned to a lower level that is equal to lactate level of other athletes.

In above case, inhaling pure oxygen indeed increased muscular reabsorbtion of oxygen, and thus option A might not be true. Isn't it?

Thanks!

AndrewN · Answer

Hello,  willacethis . I think you are reading into the question too much, rather than taking it at face value. Look at it again:

If the statements above are all true, they  most strongly support  which of the following conclusions?

There is nothing absolute or definitive about the question, as Marty Murray explained in his post just above. The answer is a could-be-true, based on what the passage says. If you can provide a reason for why any other answer choice is  more strongly supported  by the passage, then I think the community could benefit from hearing your thoughts. As for me, I believe the process of elimination points to (A) as the top contender.

- Andrew

ArathyA · Answer

Passage Analysis: 
•Many athletes inhale pure oxygen after exercise in an attempt to increase muscular re-absorption of oxygen. 
  o A lot of athletes follow the practice of inhaling pure oxygen instead of atmospheric air after exercise. They do so in order to increase muscular re-absorption of oxygen.

•Measured continuously after exercise, however, 
  o A contrasting phenomenon is observed when a measurement is conducted continuously after exercise.

•the blood lactate levels of athletes who inhale pure oxygen are practically identical, on average, to those of athletes who breathe normal air.
  o On average, more or less identical blood lactate levels are observed for both type of athletes; the ones who inhale pure oxygen and the ones who breathe normal air.

•The lower the blood lactate level is, the higher the muscular re-absorption of oxygen is.
  o Blood lactate level is an indicator of muscular re-absorption of oxygen, in inverse proportion.

Considering all this information to be true, we can infer that inhaling pure oxygen does not make any significant difference on the muscular re-absorption of oxygen after exercise.

Question stem analysis

“If the statements above are all true, they most strongly support which of the following conclusions?” 
 We have to determine which among the options supports the statements in the passage most strongly.

Answer Choices 
 (A) Athletes’ muscular re-absorption of oxygen is not increased when they inhale pure oxygen instead of normal air.
 Correct 
This statement is in line with our passage analysis. There is no significant difference in the muscular reabsorption of oxygen when athletes use pure oxygen instead of normal air, which they do to increase the rate of it. Hence this is the most supported conclusion.

(B) High blood lactate levels cannot be reduced.
 Incorrect 
We know only about the relation between blood lactate levels and muscular reabsorption of oxygen. We have no information that says it cannot be reduced. Hence it is an incorrect choice.

(C) Blood lactate levels are a poor measure of oxygen re-absorption by muscles.
 Incorrect 
This option is against the passage as it clearly states there is an inversely proportional relationship between blood lactate levels and muscular oxygen re-absorption.

(D) The amount of oxygen reabsorbed by an athlete’s muscles always remains constant.
 Incorrect 
This is an unsupported generalisation. We do not know anything regarding the consistency of amount of oxygen reabsorbed by one particular athlete. All we know is that after exercise, the rate of reabsorption of oxygen by muscles is almost the same for both who inhale pure oxygen and those who inhale normal air.

(E) The inhaling of pure oxygen has no legitimate role in athletics.
 Incorrect 
Another unsupported generalisation. We do not know if inhaling pure oxygen has any other effect on the physiology of the athlete that may affect her/his performance on the track.

brains · Answer

MartyTargetTestPrep  ,  GMATNinja  ,

I have one doubt in option A. The passage says that  on average  the blood lactate levels in athletes who inhale pure oxygen is same as that in case of athletes who inhale normal air. Now when it is said as average, we can say in some athlete who breathe pure oxygen ,lactate levels in blood must be lower than average. In that case , muscular reabsorption will be higher. Statement A says that muscular reabsorption is not increased in athlete who inhale pure oxygen. As we saw above, given the inference definition, it must be true. While this is not the case here, then how can A be the answer. According to A, it is not on average but in all cases. If answer would have may or may not then i would have agreed.

thoughts?

MartyTargetTestPrep · Answer

Generally, within the set of values that make up an average, there will be some values that are higher than that average and some values that are lower than that average.

Regardless of that fact, the average is still the average. So, we can support a conclusion by comparing averages.

Consider this alternative example.

Let's say someone were to suggest using a certain fertilizer to make plants grow. Now, what if the average size of the plants that were treated with that fertilizer were the same as the average size of the plants not treated with fertilizer? Wouldn't it make sense to conclude that the fertilizer does not make plants grow, even if some plants treated with the fertilizer were bigger than average? After all, on average, there would be no difference between the treated plants and the untreated plants. So, there's no reason to believe that the fertilizer has any effect on plant growth.

Now, in the case of the scenario presented in this question, we have two sets of people, those breathing pure oxygen and those not doing so. On average, their results are the same. Sure, some people who breathe pure oxygen have lower than average lactate levels. At the same time others who breathe pure oxygen have higher than average lactate levels. Similarly, among those who do not breathe pure oxygen, some will have lower than average lactate levels., and some will have higher than average lactate levels.

So, the point is that, pure oxygen or no pure oxygen, you get pretty much the same lactate situation. So, apparently, breathing pure oxygen doesn't make any difference.

One additional point - notice that this question is not an Inference question, it's a Conclusion question that asks for the "most strongly supported" conclusion. So, the correct answer does not have to be something that must be true given what the passage says. I has only to follow logically from and be supported by what the passage says.

Jainam24 · Answer

Many athletes inhale pure oxygen after exercise in an attempt to increase muscular re-absorption of oxygen. Measured continuously after exercise, however, the blood lactate levels of athletes who inhale pure oxygen are practically identical, on average, to those of athletes who breathe normal air. The lower the blood lactate level is, the higher the muscular re-absorption of oxygen is.

If the statements above are all true, they most strongly support which of the following conclusions?

(A) Athletes’ muscular re-absorption of oxygen is not increased when they inhale pure oxygen instead of normal air. 
(B) High blood lactate levels cannot be reduced. 
(C) Blood lactate levels are a poor measure of oxygen re-absorption by muscles. 
(D) The amount of oxygen reabsorbed by an athlete’s muscles always remains constant. 
(E) The inhaling of pure oxygen has no legitimate role in athletics.

My POE is as follows: 
(E) Can't really say this. Inhaling pure oxygen may not help an athlete's muscles but may help his/her mind. Reject E 
(D) Why would the athletes attempt to do that post excercise then as stated in first sentence of the prompt? The says that the 1st sentence is false however, it is told that all sentences are true. So reject D
(C) False. The last statement gives us the correlation. Reject C
(B) Can't conclude from the given information. We don't know whether athletes have high blood lactate levels post excercise in the 1st place itself! Reject B

By POE A is the ans as in my attempt I had rejected A but since it is the "least worst" option of the lot, it is the answer

Many athletes inhale pure oxygen after exercise in an attempt to

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