The doldrums is the name of a place in the ocean typically found between 5° north and 5° south of the equator, and is also known as the Intertropical Convergence Zone (ITCZ). The doldrums are characterized by unstable trade winds and oftentimes, ships caught in the doldrums can be stranded due to lack of wind in the belt of calms and very light winds.
There are people who will tell you that the expression “in the doldrums” alludes to the maritime doldrums,. However, the region now called the doldrums wasn’t named until the mid-19th century. The earliest known reference to the region’s name in print is Matthew Maury’s The Physical Geography of the Sea published in 1855 that states:
The equatorial doldrums is another of these calm places. Besides being a region of calms and baffling winds, it is a region noted for its rains.
So where does the expression come from if not from the maritime doldrums?
The word doldrums was used to mean a general state of low spirits in the early 19th century. For example, in private correspondence from Sir Thomas Lawrence to Lady Morgan on December 21, 1810. Sir Lawrence wrote:
My evil genius does haunt me, my dear madam, but not in your shape on the contrary, I believe that it takes you for my good one, for it is very studious to prevent my seeing you. To morrow I cannot, Sunday I cannot; but I will make it as early in this ensuing week as my distractions will admit.
“Doldrums and bother,” are weak terms for ladies of your invention at least, they touch not my state.
The Oxford English Dictionary defines the doldrums in its archaic and obsolete form as meaning a dull, drowsy, or sluggish fellow. It comes from the Middle English word dold which is from the Old English Word dol. The past participle of dold is dullen. The word doldrum dates back to 1795 when the word dold meaning dull with the addition of the suffix rum or rums, to indicate the plural form thus indicating that the person to whom the doldrums referred was suffering from low or dull spirits.
Historically Speaking 