Exercise and the First Law of Motion

Every object in a state of uniform motion tends to remain in that state
of motion unless an external force is applied to it. -- Newton's First
Law of Motion

I guess it shouldn't be a surprise me that once I get moving I want to
keep moving. But I am always happily surprised each time I start working
out again. It gets easier the next day to continue. Once you've
experienced this you start to understand that exercise doesn't make you
more tired, it makes you more energetic.

I ran another 2 miles today and played game of tennis with a neighbor
the other night. I would have never played tennis at 9:00 at night had I
not already been in the groove of active motion during week. I would
have been too tired.

The trick to all of this, I guess, is to keep the external forces out of
your life that stop you. Remove the roadblocks. There are mental ones
and physical ones.