That goes back to reply #1 about muscularity giving a younger appearance.
When my youngest son was 15 he was 5’11" and muscular. He also is an old soul that presents much older than he really is. We let him spend the day on campus with his college aged brother. By the time we’d picked him up later that night two different young women had asked him to their sorority semi-formal. He loved it, but he never told them he was only 15. He did tell us he was amazed at how small and young looking a lot of the guys on campus were.
Older–knows how to manually change stations on the TV; knows how to use a rotary dial phone; checks his or her answering machine daily; actually goes into the bank & deals with a teller; has met someone in person before dating him or her; refers to microwave meals as TV dinners;
Younger–does none of the above.
Older–knows how to have a discussion without the use of an electronic device.
Younger–cannot function without an i-phone.
Word choices.
This is true. If they just removed a few aging words like “pocketbook” and “slacks” from their vocabulary, I think some people would seem a decade younger.
Older: blames youth constantly for being tech dependent.
Plenty of runners are not thin. Go watch a 1/2 or a full - plenty of people running and completing the race that are fit for the race - meaning they can handle it and complete it - but in terms of physical features like weight, you may not outside of a race know they are a runner.
I’m a thin marathon runner and I don’t think I look older than I’m supposed to look! I have a lot of old, thin running friends- some look old and gaunt and some don’t. As @abasket pointed out, there are many distance runners who aren’t waifs- even in the elite ranks, once you get past the Kenyans and Ethiopians. A lot of it has to do with sun exposure throughout your life, I think. Some is just genetics.
H is a thin former marathon runner. I think his marrying a much younger woman (me) makes him seem younger than he is. The fact that he stays trim and fit helps a great deal.
Balding sadly does age people.
Melanin, we tend to always looks much younger than our age as a race.
Younger- snow sports
Older- snow birds
Younger casual- no belt
Older casual- belt
Younger: the word “like” in every other sentence
Older: “I’ll give you $10 if you can keep from saying “like” for 30 minutes.”
Like I bet you get a lot of likes on that one. 
@rockymtnhigh2 …lot of the influencers wear belts, especially Gucci. Even so, I think they are youthful if they have a cool bigger buckle.
Didn’t realize no-belt is “younger” … tis just my lazy habit.
older- thickly applied foundation makeup
younger- thinly applied or transparent foundation makeup
older- says ‘TV’
younger- says ‘internet’
older- says ‘read in the paper’
younger- says ‘read online’