Exercise for longevity but don't over-exercise?

How do we exercise for longevity without over-exercising in a world filled with "fitspiration" because along with the advent of the ‘gym and fitness craze’ comes a lot of compulsive over-exercising. Exercising that consumes your life leads to:

bigorexia (muscle dysmorphia focussed around being big and muscular)
exercise bulimia (exercise being used to burn up calories)
and what I think of as health-o-rexia (exercising compulsively to stay fit and healthy.)

over-exercising doesn't lead to health or longevity

Alan told me this about his fitness obsession: "...I had 4 coaches (Gymnastics coach, Resistance Training and Posing Coach, Movement Coach and weight-lifing Coach). I also had a "Diet Coach" who monitored what I ate. I spent 4-5 hours a day in the gym."

Julie told me: "I'm that obsessed person, who can't go a day without exercise - EVER! Most days, I do 3 exercise classes and go for a cycle. If I have to choose between seeing friends of exercising, exercise will always win. It's my way of staying healthy."

I certainly flirted with exercise bulimia in my 20's when I was running like a crazy woman and cycling everywhere, all because it was the best way to burn up calories and 'speed up my metabolism.

But none of these scenarios is a way to exercise for either health or longevity.

Over Exercising doesn't lead to longevity

As I study the lives of centenarians, this is what I discover. Most of them walk a lot either because they enjoy it or because it's just a natural part of their lifestyles. They have naturally active lifestyles - such as gardening, or doing their own maintenance etc.... They do believe in keeping their bodies strong so they can remain functional and some I've come across do a set of daily stretches to keep supple.

But I've never come across one that

is obsessed with how big their muscles are,
wears a fitbit and obsessively monitors their steps or activity
is overly concerned with exercising at an aerobic rate
exercises as a way of controlling calories

Symptoms of over training and robbing your healh

You often have small niggly injuries and sometimes these turn into bigger injuries

You feel tired and fatigued and your musles feel fatigues

You have a persistent elevated heart rate

You feel de-motivated

You may feel depressed and irritable

People may tell you you've had a personality change

You become more suseptible to small infections