Oh my, you want to know this. Dr. Ellen tells us that we are holding dynamite. Actually, those are my words but check out this post called, Use it or Lose it - Rewire Your Brain in Daily Doses. Here's a snippet:
While you sleep at night, your brain takes on the enormous task of rewiring itself, based on what you did during the day. It’s how the plasticity in the human brain can work for or against you.
For example, if you organize your day into a schedule to get more done – you grow dendrite connectors for organization. Simply act on a target you set – and the brain’s plasticity will rewire for sharper focus for the following day. Plasticity can also work against you though.
Why do I interpret this to mean we are holding dynamite? One way or the other, there's a big reaction. If we reinforce bad habits and behaviors, we are hurting ourselves. If we use this gift - this power - to recraft our brains for success and health, BAM!, that's a breakthrough.
It's up to us to choose and then live with - hopefully enjoying - the consequences. Imagine that if we walked a half mile to the bank each day, the bank would put $1000 in our account. On days we don't walk to the bank, they deduct $1000. We can choose each day to take the walk or pay a grand in penalties.
And we all know that walking every day is good for our health.