The 14th day of every lunar month or the day before the new moon is known as Shivarathri. Among all the twelve Shivarathris that occur in a calendar year, Mahashivarathri, the one that occurs in February-March is of most spiritual significance.
On this night the northern hemisphere of the planet is positioned in such a way that there is a natural upsurge of energy in a human being. To allow this natural up-surge of energies to find their way - you remain with your spine vertical, or you stay awake. Modern science has gone through many phases and arrived at a point today where they're out to prove to you that everything that you know as life, everything that you know as matter and Existence, everything that you know as the cosmos, as galaxies, is just one energy, which manifests itself in millions and millions of ways.
This scientific fact is an experiential reality in every yogi. The word “yogi” means one who has realized the oneness of the Existence.
When I say “yoga,” I'm not referring to any one particular practice or system; all longing to know the unbounded, all longing to know the oneness in the Existence is yoga. .
People who are on the spiritual path, have special sadhanas on those days, because on that day in the month, there is a natural upsurge of energies in the human body.
The puranas say, “Blessed are those who spines are erect”.