Answer: It’s not only physical but also mental stress because you have to hear, respond to, and evaluate everything. You are pulled into and held there, and it is a high-quality action.
Question: How important is it to stay and make this effort, rather than release tension by taking a smoke break?
Answer: No, not in any case. No smoke breaks! A person must overcome himself and not be worried about his heart or head. Nothing will happen to him. The tension is really strong, but it happens under the influence of the upper Light, so there can be no unpleasant side effects.
From the Virtual Lesson 5/20/12, “Fundamentals of Kabbalah”