Those people have trained very deliberately over years to reach that level of performance, on top of an innate genetic disposition.
Undoubtedly, in absolute terms they have a higher capacity to withstand the negative physical effects of psychosocial stress as described in the paper, precisely because of these physiological adaptations.
If regular people trained themselves to deal with stress then they would have a higher capacity too.
The paper is referring to the maximum capacity of a particular organism at a particular moment in time. It doesn't assert that the capacity is uniform across a species or doesn't change over time.
Undoubtedly, in absolute terms they have a higher capacity to withstand the negative physical effects of psychosocial stress as described in the paper, precisely because of these physiological adaptations.
If regular people trained themselves to deal with stress then they would have a higher capacity too.
The paper is referring to the maximum capacity of a particular organism at a particular moment in time. It doesn't assert that the capacity is uniform across a species or doesn't change over time.