The more we control thought, activity and food, the more we will be able to control sleep. But moderation ought to be the rule for the sadhak (aspirant), as explained in the Gita.
As explained in the Gita, sleep is the first obstacle for all sadhakas.
The second obstacle is said to be vikshepa, or the sense objects of the world which divert one’s attention.
The third is said to be kashaya or thoughts about previous experiences with sense
The fourth, ananda (bliss),
is also called an obstacle,
because in that state a feeling of separation from the source of ananda,
enabling the enjoyer to say,
‘I am enjoying ananda,’ is present.
Even this has to be surmounted, and the final stage of samadhana or samadhi has to be reached, where one becomes ananda, or One with the Reality, and the duality of enjoyer and enjoyment ceases
in the ocean of Satchidananda
or the Self.
— The teachings of Sri Ramana Maharishi summarized by A. DEVARAJA MUDALIAR as a book: GEMS FROM BHAGAVAN.
Chapter VIII. SELF-REALIZATIO