Nineteen year old with very rapid heart beat with mild exertion, My daughter is 19, average weight. When doing mild exercise such as a brisk walk, her heart rate goes up to the 190s, which is painful and makes exercise difficult. She had a echo and stress test. Doc said 200 beats per minute is okay for someone so young. Doesn t feel right to me. She also has occasional tachycardia events which are harmless according to the doc. Any suggestions? Should we seek a second opinion?