Exertion

• Often a person's heart rate will rise if she exerts herself. For someone with low cardiovascular endurance, exertion can come from something as simple as climbing a flight of stairs or jogging across the street.
  
  

Medication

• Certain medications have been known to elevate heart rate, particularly diet drugs. To prevent an incident, it is wise to be aware of the possible side effects of any medications taken.
  
  

Panic Attack

• The University of Oregon Counseling and Testing Center points to panic attacks as a common cause of an accelerated heart beat. In fact, the heart often pounds so hard during a panic attack that the symptoms are commonly mistaken as a heart attack.
  
  

Excitement

• When a person becomes excited, adrenaline is released, causing the heart to race. Watching a thrilling movie, avoiding a car wreck or seeing an attractive person are all regular life occurrences that may cause this adrenaline flush.
  
  

Illness

• Caroline S. Rhoads, associate professor of Medicine at the University of Washington, points to illness as a possible cause of a racing heart rate. Chronic illnesses and lung diseases such as COPD and pneumonia are among the more common illnesses likely to elevate heart rate.
  
  

Heart Attack

• Naturally, the first thought a person gets when his heart is racing is heart attack. If you are experiencing any pain in relation to an accelerated heart rate or think you may be having a heart attack, it is always wise to receive medical attention.