These guys peg out their RPMs all day, every day. Working 9-10 hours/day is normal, and most people work through lunch breaks (not expected by management, but the culture is to work until the job is done).
The intensity comes from a desire to excel combined with demanding clients. Internally, the team has your back and is a safe place to be honest when you need help, but the client base in large B2B tech firms constantly press for measurable ROI for the thousands of marketing dollars they spend each month.
Some staff thrive under the pressure, but for me the fast pace, hours required to keep up, and constant pressure from clients was too much.