Effects on oxygen saturation

Updated July 19, 2017

Oxygen is vital for human survival. All the cells in our body need a certain amount of oxygen to carry out their duties. Oxygen saturation is the amount of oxygen that red blood cells carry, which attach to haemoglobin molecules. Normal saturation levels are 95 to 99 per cent. Typically, a person will only reach 100 per cent when supplemental oxygen is used. It's when saturation levels fall below 90 per cent that the body begins to suffer adverse effects.


Hypoxaemia, also called low blood oxygen or hypoxia, is when oxygen saturation falls below the normal levels. Not having enough oxygen circulating can produce many abnormalities, such as shortness of breath, tachycardia, hypertension and polycythemia. It can also cause an increase in cardiac output that eventually falls, causing hypotension and ventricular fibrillation, as well as restlessness, apnoea and many others.

Shortness of Breath

Following exercise, experiencing shortness of breath is typical. When a person is hypoxic, experiencing shortness of breath is a telltale sign that the body isn't receiving enough oxygen. To compensate, the body will attempt to take in more air; however, this may sometimes not be enough.


When there are low levels of oxygen in the blood, the heart will work harder to pump more blood throughout the body. This will result in tachycardia, or a higher-than-normal heart rate. A normal heart rate is 60 to 100 beats per minute. Symptoms include dizziness, shortness of breath, rapid pulse rate, chest pain and heart palpitations. If not treated promptly, tachycardia can lead to stroke, sudden cardiac arrest or death.


According to Medicine Net, one in three adults in the United States is diagnosed with hypertension. Hypertension, or high blood pressure, is when the heart has to work hard to pump more blood through the body. This will create a higher force against the artery walls and will lead to major health risks, including heart disease. Symptoms can include dizziness, headaches or nosebleeds; however, these symptoms don't typically arise until the blood pressure has got to dangerously high levels. Causes include kidney disease, diabetes, certain medications and others. Sometimes, no cause is identified, and it may be caused by hypertension.


Low oxygen saturation levels can also lead to polycythemia, or an overproduction of red blood cells, causing a thickening of the blood. This overproduction raises the risk of blood clotting, which can lead to strokes, heart attacks and other major health complications. Long-term oxygen deprivation, as with chronic smoking or lengthy periods spent at high altitudes, typically leads to secondary polycythemia. This typically resolves itself when the source of the oxygen deprivation is addressed. Genetic polycythemia, also called polycythemia vera, occurs over a longer period of time and is typically seen in older adults.

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About the Author

Jennifer Sobek has been a writer since 1993, working on collegiate and professional newspapers. Her writing has appeared in the "Copperas Cove Leader Press," "Fort Lewis Ranger," "Suburban Trends" and "The Shopper News," among others. Sobek has a Bachelor of Arts in journalism from Rowan University.