Slow Down

• Stop whatever you're doing and relax. Whenever your heart rate increases without physical activity, it is a sign that you need to slow down and relax. Relaxation techniques such as slow breathing may be helpful in slowing down your heart rate.
  
  

Avoid Caffeine

• Regulate excess caffeine in your diet. Caffeine is a stimulant that can increase heart rate. Avoid food and drinks that contain high amounts of caffeine. Colas, coffee, tea and chocolate all have high levels of caffeine. Diet pills also contain excess caffeine and should be avoided.
  
  

Exercise

• Exercise regularly. People who are out of shape tend to have a higher resting heart rate. Exercising regularly can improve your overall resting heart rate. Exercise also helps the heart build a better resistance to adrenaline rushes that cause a rapid heart rate.
  
  

Increase Magnesium

• Add more magnesium to your diet. Magnesium naturally improves the rhythm of the heart and can control a rapid heart rate. Ingest foods that contain rich amounts of magnesium, such as soy beans, bran, nuts and beans.
  
  

Increase Potassium

• Add more potassium to your diet. Potassium can slow the heart rate and decrease the irritability of the heart muscle fibers. Ingest fruits and vegetables regularly, as they are rich sources of potassium. Limit excess sodium in your diet because sodium depletes the potassium in your body.
  
  

Monitor Sweets

• Decrease the amount of sugar in your diet. Foods with sugar naturally contain adrenaline, which can increase your heart rate. Instead of sugary snacks and soft drinks, eat more healthy and natural foods such as fruits and vegetables.