If you exercise regularly, you're probably familiar with that tired feeling that creeps up on you during a workout --- your muscles start to quiver, you feel out of breath and an overall sense of fatigue sets in. It's caused by a lack of oxygen. Professional athletes train hard to try and overcome this lack of oxygen, allowing them to run faster, jump higher, pedal faster or play harder than before.
Identification
According to the American Association of Critical-Care Nurses Procedure Manual, oxygen saturation is a measurement of how much oxygen your blood carries as it circulates through your body. Often abbreviated SaO2, oxygen saturation can be measured using pulse oximetry. The completed measurement is abbreviated SpO2. An accurate measurement depends on several factors, including your body temperature and the amount of light the sensor picks up.
Average Oxygen Saturation
In "Exercise Prescription: Physiological Foundations," author Kate Woolf-May writes that most healthy people have an average resting oxygen saturation of 95 to 98 percent. When you exercise, Woolf-May notes that your saturation level drops. If it reaches approximately 85 percent, you'll start to feel out of breath.
Oxygen Saturation vs. Oxygen Consumption
Oxygen saturation is closely linked to oxygen consumption --- the more oxygen you take in, the more oxygen is potentially available for saturation. Professional athletes often try to improve their VO2max, or maximum oxygen intake level. According to Werner Hoeger and Sharon Hoeger in "Lifetime Physical Fitness and Wellness," your VO2max depends on your fitness level along with your gender, age, body type and genes. To raise your VO2max, they recommend training at high intensity levels that elevate your heart rate to between 147 and 180 beats per minute. This intensive training builds your body's capacity for oxygen consumption.
Benefits of Raised Oxygen Consumption
When you raise your VO2max, your muscles absorb more oxygen from your blood. According to Barry A. Franklin in his essay "Cardiovascular Responses to Exercise and Training," training at high intensity levels can increase your heart's output, increase your body's amount of oxygen-absorbing enzymes and increase the density of capillaries in your muscles. In other words, increasing VO2max is as much about distributing oxygen more efficiently as it is about increasing the amount of oxygen you can take in.
Exercise and Oxygen Saturation
Although exercise can increase your VO2max, it will not raise your oxygen saturation; in fact, it will actually decrease the amount of oxygen in your blood. According to iWorx, a provider of hardware and software for physiology labs, healthy individuals who engage in vigorous exercise can deliver more oxygen to their muscles during a workout than those who aren't as physically fit. Because these muscles absorb more oxygen, less is readily available in the bloodstream at any time, leading to a lower overall percentage of oxygen saturation. This decrease is actually a benefit of exercise --- it means your body is capable of providing your muscles with the resources they need to keep going.
References
- American Association of Critical-Care Nurses: Oxygen Saturation Monitoring by Pulse Oximetry
- "Exercise Prescription: Physiological Foundations"; Kate Woolf-May; 2006
- "Lifetime Physical Fitness and Wellness: A Personalized Program, Tenth Edition"; Werner W.K. Hoeger and Sharon A. Hoeger; 2009
- "Exercise and Sport Science"; edited by William E. Garrett, Jr. and Donald T. Kirkendall; 2000
- iWorx: Experiment HE-3: Exercise, Blood Pressure, and Oxygen Saturation Levels
