Oh, I think I misread it. In this case I think the comment is actually saying that a plan to retire at 40 might be derailed by spending a couple years out of work in hospital at 28, thus losing your income at least temporarily and possibly spending your savings. A lot of this can be mitigated by having the right insurance, but once you aren't working it can be harder to afford insurance that will cover really good care.
What I was thinking of was that many people don't want to work very hard now to gain rewards later when there is a risk they won't live until later to enjoy it. So they do things like take a few years off at 27 and then go back to work until, say, 38, instead of working straight through until 34 and retiring permanently then.
