Reflux of blood in veins is usually not a problem, but it can cause swelling over time and needs to be taken seriously. Venous blood reflux refers to the backflow of blood in the veins that does not flow in the normal direction, usually due to prolonged squatting, sitting, etc. If it does not last long, it does not affect your health, so it does not matter. However, if the venous blood flows backward for a longer period of time, it will also cause swelling, soreness, fatigue and other adverse reactions, so it is better not to keep a position for a long time to avoid making the body to have venous blood flow backward. Venous blood backflow can not be ruled out due to venous stasis in the lower limbs, if this is the case you need to pay attention to, it is best to go to the hospital in a timely manner to carry out the relevant examination, and then carry out targeted treatment.