Disclaimer: Our field is extremely competitive (deep learning) and other labs may have better working styles depending on their lab size and member composition.

My lab's workload on average is 8 - 12 hours a day for 6-7 days a week, ramping up even more closer to deadlines. That being said, a lot of this time (50% or more) is for thinking and discussing. This schedule, while hard, seems to be effective for publishing in good conferences.