I tend to increase the structure in my life during big assignments rather than let it slip as most people do.If you remember that all you need to keep yourself fresh is good quality food, 7 hours peaceful sleep and, perhaps as important as the others but most often overlooked, regular exposure to fresh air.Don't drink more than a pint or two or a large glass of wine to unwind and politely drop out of any non core engagements that you have.Don't be tempted to try to woak all of the time you are awake, your effectivness drops off the scale as you reach exhaustion. Instead, try to add structure by working three twelve hour shifts with thirty mins breaks for food and a walk in between.This works for me, and compared to my colleagues who seem to flap and whinge and start eating crap and drinking more as the pressure grows, it seems a better choice.And no, I am not an anodyne robot, I just prefere to get the work done and party at the end!