You’ve probably heard the lines about how “40 is the new 30” or “30 is the new 20.” What is this based on? Are they just lines to make older people feel younger? Is it based on how you feel? Is there science involved?
In my quick searching a couple of weeks ago, the results showed a mix of reasons.
For example, “50 is the new 20” was especially common because there was some article that cited some research that suggested those who were 50 years old could still be as fit as a 20-year-old. The article was published and republished in various places.