The mitral valve is on the left side of the heart. It lets blood flow from the upper to the lower heart chamber. Mitral valve regurgitation is diagnosed when the mitral valve in the heart does not close well, which causes blood to leak back from the left ventricle into the left atrium. Mitral valve regurgitation forces the heart to work harder to pump extra blood out of the heart.
Measurement of a track. The proper length for a competitive running track is 400 m (1,312.3 ft). Some tracks are not built to this specification, instead some are legacy to imperial distances like 440 yd (402.3 m). Prior to rule changes in 1979, distances in Imperial units were still used in the United States.
The 10,000-meter race is the longest standard track event. On a standard outdoor track (400 meters) you would need to run 25 laps to complete a 10K. On a standard indoor track (200 meters) you would need to run 50 laps to run a 10K.