Why Do Our Arms, Legs, and Feet Fall Asleep?

Have you ever wondered why, after sitting with your legs dangling in the air, you eventually lose feeling in your legs? Don’t worry, you aren’t slowly becoming paralyzed; they have simply “gone to sleep”. The same thing goes for your arms too; they just go to sleep sometimes, even when you’re wide awake, particularly when you’ve been putting a lot of pressure on them.

Now, when you experience these conditions, no matter what you do to wake your limbs up, those lazy parts stubbornly remain dozing, making you question your authority over your own body parts. Eventually, they’ll start waking up, but it can be a long and painful process!

So… Why do our arms, legs, and feet go numb sometimes?

Occasionally, these parts of our body fall asleep at the worst possible time, like when you are watching a rom-com with your date, and she wants you to put your arm around her. Unfortunately, your arm is like, “Sorry, man, that movie was garbage. I fell asleep.” Your date isn’t happy, but your arm certainly is. But why does this happen?

It’s All About Nerves

The reason why your body parts fall asleep is similar to the working of a hose. If you’ve ever gardened, then you must be familiar with a hose. The water flows through the hose normally if no pressure is applied to it. However, if someone was to step on the hose, the water coming out of the nozzle would diminish. If someone was to stand on the hose and exert all their weight on the hose, the water would eventually stop coming out of the nozzle entirely.

standing on hose

You usually experience a feeling of numbness in your body parts when you lean heavily on your arm or sit cross-legged, etc. When you are in these positions, extra pressure is being exerted on the body part, so the signals sent by the nerve to that body part becomes abnormal. When pressure is applied for a prolonged period of time, the nerve signals to that body part eventually stop, just like water coming out of a hose.

Why do body parts go to sleep?

Nerve impulses are responsible for carrying sensory information from nerve endings in the body to the brain, along with instructions from the brain to various parts of the body. When extra pressure is applied to a particular part of the body, it results in the squeezing of these nerve pathways and your brain struggles to tell the body part what to do. As a result, you lose feeling in that body part.  In medical terms, this phenomenon is known as paresthesia.

arm falling asleep

Feet falling asleep

Similarly, for the legs, information transmitted from the body part becomes confusing to the brain, as some nerve cells are sending erratic impulses, while other cells don’t send any information at all. This is the reason for the legs to fall asleep, and why you feel a strange tingling sensation.

How Do They Wake Back Up?

The tingling sensation you feel does have an important function besides making you feel like you’ve lost control over your limbs. The tingling is your brain’s way of telling you that your body part has gone to sleep. Your arm falling asleep for 10 minutes is not much of a threat to your health, but if it were to go asleep for several hours, it could result in nerve damage. In other words, the tingling sensation is a signal for you to re-adjust your position and keep those nerve impulses flowing properly.

Once you start moving your arms and feet around, the nerve impulses start to flow normally again. Just as a hose takes time to release water again after being stepped upon, your body takes some time to return to normalcy. During this time, you may feel a burning sensation in the affected area, which is often described as “pins and needles”. It’s an apt name, because, in those few minutes of nerve impulse recovery, that part of the body is highly sensitive and even painful, at times.

This pain is no reason to worry, however, as your body part will eventually wake up. More importantly, just focus on not letting certain parts of your body fall asleep at the wrong time!

References:

  1. University of Maryland Medical Center
  2. WebMd.com
  3. HowStuffWorks
The short URL of the present article is: http://sciabc.us/VlKV9
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About the Author:

Ashwin Vinod has a B.Tech in Electronics and Communications from APJ Abdul Kalam Technological University, Trivandrum (India). He likes to watch movies, reading fiction novels and surf the internet.

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