Can getting enough high quality sleep cancel out the harmful effects of overtime work or not getting enough vacation?
Recently, articles said that taking less than 3 weeks of vacation increases the risk of death by 37%! The study even found that a healthy diet and exercise doesn't even help but didn't seem to talk about whether sleep would cancel out the harmful effects. Subjects could report how much sleep they got and the study could take it into account. Here's one: http://www.dailymail.co.uk/sciencetech/article-6103121/Taking-3-weeks-vacation-office-year-extend-life-expectancy.html
If high quality sleep can really cancel out the harmful effects, someone could work around 14 hours five days a week without harmful effects. I left 10 hours because sleep efficiency can only go so high, and we need time for breaks, exercise, healthy eating, etc.
If sleep is the main factor, then those with insomnia need to find ways to sleep well if they want to benefit from the vacations. For those who need to catch up on sleep, it could mean half day vacations so that it's effectively a sleep vacation. Someone might start work in the afternoon so that it's possible to sleep in for a few extra days.
Correction The study actually said that the subjects slept less when taking shorter vacations.