The heart is essential to life. With each beat it pumps all the oxygen and nutrient rich blood to all the muscles and organs of the body. Heart rate is the number of times your heart beats in one minute. There are many factors that can affect heart rate. Disease, stress, body temperature, position, nicotine, caffeine, medications and activity levels all affect heart rate.
Regulation
During any activity, the amount of blood pumped by the heart must increase in order to meet the demands of the skeletal muscles. According to "Exercise Physiology: Theory and Application to Fitness and Performance," the sympathetic and parasympathetic nervous systems influence heart rate. Those systems work with the brain to adjust heart rate according to the needs of the body. The parasympathetic nervous system is responsible for the slowing of the heart rate. The sympathetic nervous system takes over when the body is working at a higher level, therefore stimulating a higher heart rate.
Resting
At rest, your sympathetic and parasympathetic nervous systems work together to maintain your resting heart rate. At rest, your heart rate should be between 60 and 100 beats per minute. A true resting heart rate is best obtained first thing in the morning before stepping out of result in an increased resting heart rate. You can measure your resting heart rate by placing your pointer and index finger on your carotid or radial pulse and count the beats for one minute. This value is your true resting heart rate. Typically, fit individuals have a lower resting heart rate compared to others of similar age. Also, the older you are, the higher your resting heart rate tends to be.
Positional
A study titled "Postural Effects on Heart Rate and Blood Pressure" supports that from the lying to sitting position your heart rate will increase. And when standing, your heart rate will be higher than when sitting. Other studies have shown that as time passes while standing, your heart rate will continue to rise slightly. Blood pressure problems can affect your positional heart rate.
Exercise
As soon as you start to move, your heart rate will again increase. Even small movements, such as swinging the arms will slightly increase the heart rate. There is a linear relationship between heart rate and exercise intensity. As the activity becomes more intense, the greater the heart rate will be. The more muscles involved in the movements, the greater the heart rate. More conditioned individuals will see less of a rise in heart rate with activity. They often have to exercise more intensely to get their heart rate into training zones. Whereas less fit individuals may see a large rise in heart rate with very little movement.
Maximum Heart Rate
Your heart rate will not rise indefinitely with exercise. As you vigorously exercise, your heart rate will eventually plateau. This plateau is your maximum heart rate. A true maximum heart rate can be obtained through a stress test. It is advised to only do this type of evaluation under the direction of your physician. For practical purposes, you can estimate your maximum heart rate using the formula 220 minus your age. Maximum heart rate is often used to prescribe exercise intensity.
Considerations
Any interruption in the pumping of the oxygen and nutrients to the body could adversely affect your organs and tissues. The heart should beat regularly and efficiently regardless of your activity level. When checking your heart rate the pulses should feel strong and rhythmic. You should not feel and fluttering or long pauses between beats. If you feel either of those, you should contact your physician immediately.
References
- Scott Powers & Edward Howley, "Exercise Physiology: Theory and Application to Fitness and Performance," 6th edition: McGraw Hill, 2007
- Experimental Physiology: Postural Effects on Heart-Rate and Blood Pressure
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