It is the struggle that makes us stronger

 Comfort vs Struggle

Humankind has always sought inactivity, not movement.  We conserve our calories. We take a short cut; we take the lift, not the stairs; we love to get a handy carpark. As well, up until quite recently, calories were hard to come by.  Think, hunter gatherers or subsistence farmers.  Have you ever had to fetch water.   It is heavy. One litre of water is one kilogram.  Some women still have to fetch water every day.   

It is correct, we are predisposed to sit down.  But on the other hand, here is a contradiction, every society has danced.  It is like running, but more fun.  Exercise to music in class is great.  I like to say that the music drowns out the suffering.

Keeping our strength up keeps us young.  As our muscles waste away and we become frailer.  We don't grow old and slow down, we slow down and grow old.   

Where do we find the motivation for exercise.  Daniel Leiberman is his book "Exercised" says we have two choices:- We can make it necessary, or we can make it fun.