Why You Feel Pins And Needles When Your Legs Fall Asleep
As somebody who is physically incapable of sitting “properly” — you know, the whole erect-posture-with-legs-folded-at-a-90-degree-angle shindig — I often find my limbs folded in weird ways, a life choice that gives me supreme comfort. A repercussion of the “inappropriate” sitting postures is that a random part of my body is always asleep, i.e., numb, followed by a ‘pins and needles’ sensation, and sometimes a dreaded ticklish, restless feeling. Over the years, I have gotten varied suggestions to get over the sensation — shake the limb violently, walk it off, and once, a well-meaning classmate told me to write the Sanskrit word “Om” on the numb limb. To this day, I am still not sure if she was joking.
Questionable joshing aside, these sensations were always attributed to a lack of blood flow to the area, and all the recommendations to make my limb come alive relied on getting my blood moving. This is a myth.
The condition, which is temporary, is called paresthesia. “A burning or prickling sensation that is usually felt in the hands, arms, legs, or feet,” occurs when “sustained pressure is placed on a nerve,” according to the National Institute of Neurological Disorders and Stroke. Pressure on the nerve leads to it being pinched, and thus unable to communicate effectively with the spine and brain, Rebecca Traub, assistant professor of neurology at Columbia University, told Business Insider. A common nerve in the leg that is affected by sitting cross-legged is the fibular nerve, Traub added.
Imagine the nerve is like a hose, through which electrical signals flow like water, Steven Vernino, a fellow at the American Academy of Neurology, told Business Insider. The electrical signals communicate between the spine, brain, and limb, but when pressure is applied in a certain way, the nerve gets twisted, blocking the pathway for electrical signals to pass, he said. When the pressure is removed, the nerves untangle and result in paresthesia, which encompasses all the sensations that follow the initial numbness.
While paresthesia is most often incidental and random, it can also be a result of a neurological disease or lasting nerve damage, according to National Institute of Neurological Disorders and Stroke. If the feeling is chronic, or becomes more frequent, then a host of reasons could be attributed to: central nervous system disorders, such as stroke; multiple sclerosis that hampers communication between the brain and the body; transverse myelitis that affects the spinal cord nerves and their ability to carry messages; and encephalitis, or inflammation of the brain; a tumor pressing up against the brain or spine; or severe carpal tunnel syndrome that leaves nerves damaged, according to the agency.
If your paresthesia lasts too long or is happening too frequently, and isn’t occuring from unusual sitting choices, then please go get checked out.