What Affects Heart Rate

Introduction

Your heart rate is the speed at which your heart beats. Each time your heart beats, it propels blood carrying nutrients, oxygen and toxins through the body to their necessary locations. Too low a heartbeat can result in these important functions not being able to be completed. Too high of a heartbeat can result in the wearing out of the heart muscle or the hardening of the walls of the vessels that transport the blood throughout the body.

Stress

Stress is one of leading causes of a heart rate change. When your body becomes stressed, whether it be emotional or physical stress, the sympathetic nervous system kicks in and releases adrenaline into the bloodstream. One of the side effects of adrenaline is an increase in your heart rate. As the stress is relieved, the body will stop releasing adrenaline, allowing the heart rate to return to normal. Any residual adrenaline will be metabolized through the body and excreted as waste.

Infection

The presence of an infection can also affect the heart rate. This is a symptom of an immune system response to the infection. An increased heart rate allows the needed immune cells (such as white blood cells) the ability to get to the infected area at a faster pace. As the infection subsides, the heart rate will decrease.

Rest

A relaxed or sleeping state can also affect your heart rate. When your body is at rest, there is less need for oxygen in the muscles and other tissues of the body. This is a result of most of the body not performing work. In response to this lowered need, the heart rate decreases, which puts less stress and the heart and blood vessels and lowers the amount of oxygen being pumped throughout the circulatory system.

Medications

Certain medications can also affect your heart rate. For example, opiate medications, such as codeine or morphine, can dramatically lower your heart rate. Stimulant prescription medications such as Adderall or Ritalin can dramatically increase your heart rate. Illicit drugs can also affect your heart rate. For example, heroin can slow your heart rate, in some cases so low that it can cause a medical emergency. "Uppers" such as cocaine or ecstasy can dramatically increase your heart rate, which also can cause a medical emergency if the heart rate increases enough to cause the heart to stop.

Exercise

Both the level of exercise being done, as well as your fitness level can also affect your heart rate. As you exercise, your muscles require more oxygen to gain the energy needed to do work. To fill this need, both your breathing rate and heart rate have to increase. Your level of fitness will also affect how fast your heart rate increases. Someone who exercises on a regular basis will be able to perform faster and longer before needing an increase in heart rate than someone who is for the most part inactive.

References

• Mayo Clinic
• Partnership for a Drug Free America