In the human body, the heart, lungs and blood vessels work together to deliver oxygen and other nutrients to the organs and tissues. The heart pumps oxygenated blood throughout the body. The deoxygenated blood returns to the lungs, where it receives oxygen and returns to the heart for delivery to other tissues. Pulse and oxygen saturation levels help medical professionals determine if the circulatory and respiratory systems work properly.
Normal Ranges
Normal pulse rate ranges from 60 to 100 beats per minute, according to Dr. Edward R. Laskowski of MayoClinic.com. Several factors influence pulse rate in humans. This rate varies based on body position, body size, stress level, fitness level, medication use, air temperature and activity level. Normal oxygen saturation level ranges from 95 to 100 percent, according to Harvard Medical School. This means that 95 to 100 percent red blood cells are saturated with oxygen when they pass through the lungs. Oxygen saturation levels change in higher altitudes and in diseases that affect the heart and lungs.
Identification
A medical professional determines pulse rate by placing his index and middle fingers on the underside of a patient’s wrist and feeling the pulse of the radial artery. He then counts the beats for 60 seconds. Some medical professionals take the pulse using an artery in the neck, temple, groin, back of the knee or top of the foot.
Pulse oximetry determines oxygen saturation levels. This technology involves the use of infrared light and red light. Red blood cells containing oxygen absorb infrared light and allow red light to pass through them. Red blood cells with reduced oxygen levels allow infrared to pass through and absorb red light. A medical professional attaches the pulse oximeter to the patient’s finger, where a photodetector receives the infrared and red light signals. The pulse oximeter calculates the ratio of red to infrared light and converts that ratio into an equivalent oxygen saturation value.
Heart Rate Problems
Several medical conditions cause abnormal pulse rate or oxygen saturation level. Doctors refer to a high pulse rate as tachycardia and a low pulse rate as bradycardia. MedlinePlus defines tachycardia as a pulse rate above 100 beats per minute. Causes of this condition include heart damage, congenital heart defects, smoking, heavy alcohol usage, hypertension, caffeine consumption, medication side effects, hyperthyroidism, electrolyte imbalance and illegal drug use.
The American Heart Association defines bradycardia as a heart rate lower than 60 beats per minute. Causes of this condition include heart muscle damage, electrical problems in the heart and problems with the sinoatrial node, which controls the rate of the heart. Metabolic abnormalities may also cause a slow heartbeat.
Oxygen Saturation Problems
MayoClinic.com classifies oxygen saturation levels below 90 as low and oxygen saturation levels below 80 as severe. This condition, also known as hypoxemia, indicates a problem with the heart or lungs. Causes of hypoxemia include emphysema, airway obstruction, chronic obstructive pulmonary disease, pneumonia, pulmonary embolism, pneumothorax and interstitial lung disease. Patients in shock may also have low oxygen saturation levels.
Warning
Because pulse rate and oxygen affect the heart and lungs, seek medical advice any time you have an abnormal pulse or oxygen saturation level. A doctor can order diagnostic tests to determine the cause of the abnormality.
