The human body secretes more pain-blocking hormones late at night than

The passage has quite a logical information. Since pain is less at night, anesthesia used is less at night. So, risks associated with anesthesia usage could be reduced by doing surgeries at night.

I am trying to think in what situation could this not be concluded. I could just get an overview type look at the scenario and could think that perhaps, let's say, if the some risk associated with doing surgery at night happens to be much more and severe than the risk associated with giving more anesthesia during the daytime, then it will become difficult to make such a conclusion.

That's the best I could think, so I moved onto the options :

1) Well... if the energy costs are less at night, it must be good for the hospital administration. How does that get linked with the risks of surgeries happening at night or to their comparison with the risks of surgeries happening during the day. I cannot infer any link as such. This option should not be having any impact or at the max, can be a mild strengthener because it favors the conclusion only mildly, but not at all a weaken statement. Incorrect choice.

2) Are we actually talking only about baby delivery related surgeries here ? I think this choice doesn't cover the scope of the argument completely. That's the first opinion. Moreover, if more babies are born at night, how does that have any impact or relation to the risks associated with surgeries at day and at nights. Again I cannot infer any such relation. This should be an incorrect choice.

3) Okay.. so here at first I thought that may be the shift in biological rhythms might be related to the shift in response of the human body to pain at day and night. But then I thought how can I make that big a relation by myself. Biological rhythm can be anything. Again, does slight shift mean significant shift ?... in fact slight shift is for the amount of light one is exposed to sunlight..does that necessarily mean that the shift will happen in the pain bearing hormone .. certainly not.. so incorrect choice.

4) If nurses and doctors get more payment while working at night, then it sort of gives an incentive to them to work more and hard at night. May be then the risk of human performance will reduce at night. This option seems to strengthen the conclusion. So incorrect.

5) So most people lack alertness at night. Can one then say that the risk in surgeries will be less. Doesn't it look like the risk is going to weigh against the benefits of low risk against anesthesia at night. This should be the correct choice.

Correct choice E

IMO E, The argument is that anesthesia risk is lower during the night, and therefore, the risk of surgery can be lowered by conducting surgeries at night. The argument which shows that the risk at night can be higher due to some other reason, is the correct answer (say a tired doctor).


(A) Energy costs in hospitals are generally lower at night than they are during the day.

Unrelated to risk

(B) More babies are born between midnight and seven o’clock in the morning than at any other time.

Unrelated to risk/surgeries

(C) Over the course of a year, people’s biological rhythms shift slightly in response to changes in the amounts of daylight to which the people are exposed.

Unrelated to risk

(D) Nurses and medical technicians are generally paid more per hour when they work during the night than when they work during the day.

Unrelated to risk

(E) Manual dexterity and mental alertness are lower in the late night than they are during the day, even in people accustomed to working at night.

Related to risk, shows that at night risks from the doctors/nurses capabilities is heightened. Therefore, the risk reduction from lower anesthesia being required is countered by the increase in this risk.

Sir/Mam,

I am convinced with Option E... but, Can you please explain why option C is not the answer...?

Sir, what I find appealing about ''C'' is that it says- a person's biological rhythm shifts- which may imply that the time of secretion of hormone might shift; consequently its effect might not be prominent at time of surgery.

But now I understand that the the words ''slightly'' and ''óver the course of year'' imply that the shift may be insignificant.

Also, we do not know whether the secretion of pain-blocking hormone is a biological rhythm.

Is that right??

Question :-

The human body secretes more pain-blocking hormones late at night than during the day. Consequently, surgical patients operated on at night need less anesthesia. Since larger amounts of anesthesia pose greater risks for patients, the risks of surgery could be reduced if operations routinely took place at night.

Which of the following, if true, argues most strongly against the view that surgical risks could be reduced by scheduling operations at night?


(C) Over the course of a year, people’s biological rhythms shift slightly in response to changes in the amounts of daylight to which the people are exposed.