They're old enough to be my grandparents — and in better shape than people half their age

At 73 to 86 years old, the four members of Team Strong Silvers still work out every day.

Amanda Goh/Business Insider

I'm 29 this year, and as the big 3-0 looms, I find myself thinking more deliberately about getting older — about the new wrinkle I recently noticed on my face, whether I'm getting enough steps and sleep, and how all of it might shape the way I feel decades from now.

The number of people 60 and over is expected to rise from 1 billion in 2020 to 1.4 billion by 2030. By 2050...