"Our alotted light speed"

"Here's what awes me: we travel through this 4-D spacetime always at a constant speed: c, the speed of light.

No matter what we do in our momentary lives, we are always truly traveling through our universe in time and space together, always at at the same rate. Let's consider a few facts that follow from this realization.

A man who sits still uses none of his lightspeed to travel through space. Instead he is travelling in time at the speed of light. He ages--in the view of those around him--at the fastest rate possible: light speed. (How's that for a philosophical argument against sloth?)

As we travel about in our daily lives, we use up a miniscule amount of our alotted light speed to move through the spatial dimensions surrounding us. We borrow that speed from our travel forward in time and thus we age more slowly than our sedentary neighbors. You've probably never noticed that fact, and there's a clear explanation why. It's only when you travel at unimaginablly high speeds that the weirdness of time becomes large enough to notice. The mathematical reason for this is that the effect of time dilation at a particular speed "v" is only (v/c)²."

http://www.realclearscience.com/blog/2015/11/the_most_amazing_fact_i_learned_in_physics_class.html