I sneezed while lying on my front this morning, and it set my heart rate off to about 220-250bpm. This also happens whenever i do some thing like jump from height or make a sudden movement.The increased heart rate can last from any time between 10 minutes to 5 hours.I am 25 years old and have an inverted sternum, which i believe is a cause of the heart problem, as i feel it rubbing against my heart, however i am not a medical professional, so i can t say for sure.