Title What is baseballâs âmodern eraâ? The start of the 20th century might not seem particularly modernâafter all, there were only 45 states in the Union, hardly anyone owned a car (the Model T didnât debut until 1908) and William McKinley, a Civil War vet, occupied the White House.
Causes. Exercise is a common cause of rapid heart rate. Your heart rate should elevate during exercise, but it may be a problem if your heart rate remains elevated for more than 10 minutes after you finish your workout. Dehydration can also cause a faster heart rate.xercise is a common cause of rapid heart rate. Your heart rate should elevate during exercise, but it may be a problem if your heart rate remains elevated for more than 10 minutes after you finish your workout.
A rapid or fast heartbeat is when your heart is beating faster than normal. A normal heart rate is 60 to 100 beats per minute. Tachycardia is considered a heart rate of greater than 100 beats per minute.If you are exercising, or performing any kind of activity, your heart will normally beat faster. For rapid heart rates that are caused by shortness of breath, you may have trouble lying flat in bed, and you may have to sleep on 2 or more pillows. 2  Your shortness of breath may cause you to wake up in the middle of the night.