I find that nearly all private tutoring is quite intensive for both me and my students. The concentration, focus, attention, demands are often more than the students are prepared for when they seek tutoring. It's hard for someone who's never received private instruction to know how difficult it can be. Maybe for this reason, many students don't last beyond 10-20 hours of instruction.
Especially in my area of ESL, lower-level students who claim they want to improve their skills quickly find that the work is too intense to sustain for long periods. Is there any way for a tutor to help moderate that intensity? In fact, there are a few ways, but nothing will fully alleviate the pressure of sitting one on one with a tutor. Taking a short pause is sometimes helpful, lightening up the mood, digressing to some personal asides, making a small joke, reflecting the focus back onto the tutor, are small actions that can relieve the focus. Yet learning any language, including English, from a lower or beginning level is extremely hard. Despite all my experience, I find few students are prepared for the reality of the length of study required, or what it will take of their outside time to study and practice beyond the tutoring session.
Just as it's very focused work for the tutor, it's equally or more intense for the student. I always remember that when I see the student flag, or become disheartened. I feel one of my main tasks is to show students the reality of their choice to receive one-on-one tutoring, and to help them make the most of it, however intense it feels.