I'm a firm believer that the majority of premature illnesses are caused by one thing. Stress.
The best advice I can give is don't get stressed or annoyed during the day to day operation. Delays happen, weather could be bad, handling could be incompetent. If you're on the Saturday night Rhodes, is there any point stressing about a five minute delay on departure due to a lack of ground staff? You're not going to see your bed until 7am anyway.
The rest is just a part of the career we've chosen. Is it really more unhealthy to sit in the left seat of a jet on shift patterns, whilst earning six figures, compared to sitting in traffic for 1-2 hours per day to sit in an office doing a job you probably don't care about for less than half? A lot of pilots, particularly those on legacy contracts, simply can't relate to the stresses and strains of a 'normal' job on a 'normal' salary, struggling to make ends meet and putting food on the table for the family. This, to me, is far more damaging to one's health than the physical stresses and strains of our profession.
Of course, a lot depends on the airline and operation you've signed up to. If I had to do another 30 years of high intensity low cost short haul flying in its current form, I wouldn't expect to make it to retirement.