> 65 is only middle-aged if you plan to live to 130...
60 is a more usual endpoint, but...
It's a range. The middle of that range is 55, so following that math it would be 110, not 130.
But as the other reply points out, it's the middle section of being an adult. So if you take that 45-65 range, and treat it as the exact middle of your adult life, then you get 92, which is a bit high but not crazy. If you take that 45-65 range and assume old age will be the same length, you get 85, which is pretty close for wealthy non-US countries.
