The effects of constantly working12 hour shifts are a numbing tiredness that impacts your ability to do your job, and your family life. Sounds good - 3 on, 2 off or 4 on 4 off. This just means you work weekends like any other day.  In work, your tolerance drops and your colleagues are the same, so sniping and anger are frequent emotions.When you ARE off, you are just too knackered to do much else. How can a carer give the same standard of care at 7pm as she does at 7am ? How can a production operator maintain productivity on the line running at full pace for 12 hours ? Do you want a technician checking your test results in the last 20 minutes of his third 12 hour shift? In 2022 it is scandalous that we are working 12 hour days. It is even worse that we just accept that's the way it is. In the 1850s, if people had accepted that profits must come first, then our children would still be working 16 hour days in mills and mines. Never mind "the four day week" - let's get the working day back down to 8 hours. For everybody's sake.