Gerontology is multidisciplinary and is concerned with the physical, mental, and social aspects and implications of aging. 

Geriatrics is a medical specialty focused on the care and treatment of older persons. 

Gerontology refers to the study of aging in humans, especially as it occurs in adults over 65. Gerontologists study the physical and mental changes that happen as a person ages. But they also zoom out to see the bigger picture, beyond a person's medical history.

Although there is no set age to define older age, age 65 is often used because this is the age that determines eligibility for Medicare insurance in the United States.  However, some people with medical conditions require geriatrics expertise at a younger age.

2 hours ago, drpaladin said:

This caused me to idly wonder what happened to Geritol which used to be hacked relentlessly on TV. Star Trek, brought to you by Geritol.

You are correct.  For a while it seemed as if every radio and early TV show throughout the 1950s and 60s was always pushing the positive aspects of those getting older to take Geritol, which sponsored many of those shows.  

Gerontologists sometimes categorized the elderly into three age groups: the "young-old" (65-74 years), the "middle-old" (75-84 years), and the "old-old" (85 years and older). This categorization helps in tailoring healthcare approaches according to the varying needs of these groups. 

Thank you @Bill W, I was not enjoying visiting all those sites talking about "OLD PEOPLE", then you posted this and brightened up my day, thanks!

1 hour ago, Bill W said:

Gerontologists sometimes categorized the elderly into three age groups: the "young-old" (65-74 years), the "middle-old" (75-84 years), and the "old-old" (85 years and older). This categorization helps in tailoring healthcare approaches according to the varying needs of these groups. 

Imagine that, I am only a "young-old", heck, a whipper snapper!

1954 HITS ARCHIVE: Young At Heart - Frank Sinatra (his original version) - YouTube

Oh, if you are curious, scientists image dying brains cells....

Scientists Image Dying Cells in the Brain for the First Time < Yale School of Medicine

1 hour ago, sandrewn said:

Thank you @Bill W, I was not enjoying visiting all those sites talking about "OLD PEOPLE", then you posted this and brightened up my day, thanks!

Imagine that, I am only a "young-old", heck, a whipper snapper!

1954 HITS ARCHIVE: Young At Heart - Frank Sinatra (his original version) - YouTube

 You didn't want to visit all those sites because you are a young-old whipper snapper. 

I'm at the next level.  I'm a middle- old. 

I wondered why Geritol elicited so many testimonials from its users, so I looked it up.  Since Geritol was marketed before Sr. multi-vitamins were marketed, this was why Geritol had so many elderly people that claimed Geritol helped them. 

6 hours ago, Bill W said:

Gerontologists sometimes categorized the elderly into three age groups: the "young-old" (65-74 years), the "middle-old" (75-84 years), and the "old-old" (85 years and older). This categorization helps in tailoring healthcare approaches according to the varying needs of these groups. 

I'm middle old according to the above, but on rainy days when my arthritis flairs, I feel old-old!