There could be books written on the subject, so I shall only make a few points as I am sure that there will be many others. Sitting for many hours on end can not be healthy, I am in my 60s and continue jogging in the hope of mitigating some of the damage. The main stress of the job is the constantly changing shift patterns. The traditional shift worker does a week of earlies then afternoons and nights so that they can get some sort of sleep pattern. The standard UK charter goes for a few earlies, maybe an afternoon flight, followed by a night or two. That is all in one week and there is no way you can adapt to that pattern. Your sleep will be messed up good and proper and I have never understood why we do it this way. Its slightly different on the LH circuit but the same results. Not too much you can do apart from try and make the best of it but I think that there is research to say that this is not a healthy lifestyle.