Comfort zone
If you have a lot of traumatization and adverse life events, be very cautious about implementing a practice of pushing yourself outside your comfort zone.
There is nothing wrong with this practice, and it is needed to help build up the ability to tolerate discomfort.
However, in my experience many folks with complex trauma are often chronically outside their window of tolerance and that is not where this type of learning and skill building can take place.
I also find that many folks with complex trauma will try to tolerate pain and discomfort that is at a 10 out of 10 when doing this type of work. That is not learning to tolerate discomfort, that is suffering.
If and when this practice is done, it needs to be done when you are generally well regulated and the discomfort you are sitting with is no more than 2-3 out of 10. And if you are unsure of the level of discomfort you should be sitting with, err on the side of less discomfort.
And the sitting with should be done in very small, short increments. Less is more in this type of practice for those who are chronically traumatized.