Numbness in LegsThe questions below were raised by visitors to the STOMP (Straits Times Online Mobile Print) website in the AskST section of the website. eMenders doctors provided the answers to the questions raised as a public health education project. The information provided below is of a general nature and should not be treated as a replacement for medical advice. You should seek consultation from a medical or healthcare professional about your specific medical condition.
Question:
Why do our legs get numb when we sit for a long time? Is it due to the inadequate blood flow?
Answer:
The legs may feel numb after sitting for long periods of time because of compression of the nerves in the leg. Circulation of both venous blood and lymph depend on the movement of skeletal muscles, which act as minor pumps, pushing blood and lymph upwards to the heart every time they contract.
When we sit still for a prolonged periods of time, there is little or no use of the skeletal muscles in our legs, which reduces the flow of blood and lymph. This may cause lymph in particular to pool in our feet (there being no central pump with lymph, whereas blood has the heart), which may cause swelling and numbness. To relieve this, make sure you flex your leg muscles regularly when sitting for prolonged periods.