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Many athletes inhale pure oxygen after exercise in an attempt to incre

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Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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15 Jun 2016, 12:37
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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.

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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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17 Jun 2016, 16:57
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AbdurRakib wrote:
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.

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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
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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18 Jun 2016, 00:40
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
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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21 Jun 2016, 00:34
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mikemcgarry wrote:
AbdurRakib wrote:
Low blood lactate level --> high muscular re-absorption of oxygen

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.
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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21 Jun 2016, 10:57
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dixitraghav wrote:
mikemcgarry wrote:
AbdurRakib wrote:
Low blood lactate level --> high muscular re-absorption of oxygen

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.

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
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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22 Jun 2016, 17:13
The argument flows so smoothly I was able to predict precisely the answer before glancing at the answer choices.
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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23 Jun 2016, 03:03
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.

-- Feels good to get correct answer ...

A is the most logical conclusion .
b is not mentioned anywhere
D and E are irrelevant
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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08 Aug 2016, 10:57
mikemcgarry wrote:
AbdurRakib wrote:
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

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

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.
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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08 Aug 2016, 11:03
AbdurRakib wrote:
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

1. Bld Lact of athletes who inhale pure oxygen = Bld Lact of athletes who inhale normal air
2. Lower the Bld Lact ------> Higher Muscular re-absorption of oxygen

Thus ,( from statement 1. & 2.) Inhalation of Pure oxygen has no effect of increasing Muscular re-absorption of oxygen

Hence only (A) follows....
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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Updated on: 23 Mar 2017, 23:56
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.
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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24 Mar 2017, 03:19
This is pretty straight forward conclusion.

Blood lactate level remains identical irrespective of pure or normal O2.
So, re-absorption of oxygen will also remain identical.
Hence,
A) Athletes’ muscular re-absorption of oxygen is not increased when they inhale pure oxygen instead of normal air.
Correct.
B) High blood lactate levels cannot be reduced.
No mention. It remains identical only this case, i.e., inhaling pure/ normal O2.
C) Blood lactate levels are a poor measure of oxygen re-absorption by muscles.
Not mentioned.
D) The amount of oxygen reabsorbed by an athlete’s muscles always remains constant.
No. it is false as it is inversely proportional to blood lactate level.

E) The inhaling of pure oxygen has no legitimate role in athletics.
Out of scope.
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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15 Apr 2017, 02:12
AbdurRakib wrote:
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.

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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.
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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23 Apr 2017, 04:29
Do you understand phrase "The lower X, the higher Y" as "lower X <-> higher Y" or as "lower X -> higher Y"?

If there's no equivalence, (A) doesn't seem a good answer here.
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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14 Sep 2017, 08:36
lohitkc wrote:
mikemcgarry wrote:
AbdurRakib wrote:
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

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

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.

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.
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Re: Many athletes inhale pure oxygen after exercise in an attempt to incre  [#permalink]

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14 Sep 2017, 17:12
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Squib17 wrote:
lohitkc wrote:
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.

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.

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
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