8 Signs of a Blood Clot You Should Never Ignore, According to Doctors

A racing heart

When oxygen is low, your heart rate goes high to try to make up for the shortage. Feeling a flutter in your chest and having trouble with deep breaths could be your body sending out an SOS that you’ve got a PE lurking in your lungs, Dr. Teitelbaum says.

“For a small blood clot, the heart rate rises in part due to chest pain, shortness of breath, and the related anxiety that these cause,” says Lewis Nelson, M.D., chair of the department of emergency medicine at Rutgers New Jersey Medical School. There is also a release of chemicals from lung tissues that leads to a rise in heart rate.

If the clot is larger, it can cause a reduction in blood oxygen content “and even changes in blood flow that lead to a compensatory rise in heart rate,” Dr. Nelson says.