It's like the average life expectancy for a commoner in Medieval times was roughly between 30 and 35, there were people around 40 who were old and some people made it to 50 or 60. But aristocrats made it to 70 years old quite often. Some even made it to 80. That is double the life expectancy of a normal commoner.
This is a distressingly common misconception. The horrendously short 'average life expectancy' figures quoted for the real-life middle ages were largely the result of a very high infant mortality rate. If you survived childhood, however, even a peasant could expect to live to 50 or 60. There has never been a period in human history when the nobility lived twice as long as everyone else.