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Pulse Oximetry during Exercise

Pulse oximetry is a non-invasive medical technique used to measure the oxygen saturation level in the blood, usually presented as a percentage saturation level (SaO2). The method involves placing a sensor, typically on the earlobe or fingertip, that emits light through the skin to determine the amount of oxygen bound to hemoglobin in the blood.

measuring oxygen saturation using a pulse oximeters measuring oxygen saturation using a pulse oximeter

How a pulse oximeter work

The pulse oximetry method was developed In the 1980's. The measurement of SaO2 by pulse oximeters is based on the same principles as for CO-oximeters, except pulse oximeters do not require taking a sample of arterial blood. The pulse oximeter measures the relative transdermal absorption of infra-red light by Hb and HbO2.

As pulse oximeters only use two wavelengths, it cannot measure the presence of any of the dyshaemoglobins. Some models assume the presence of a certain amount of dyshaemoglobins, while others do not factor these into their algorithm.

Benefits of Pulse Oximetry

Compared to direct analysis of arterial blood, pulse oximetry provides a simple, non-invasive and cheaper alternative measure of SaO2. Other advantages of pulse oximetry are that it provides immediate results and rapid response, which are ideal for testing during exercise. However, the validity of the measurement of SaO2 by pulse oximetry has been questioned, and many studies have investigated this.

Pulse Oximetry During Exercise

There are many uses of pulse oximetry for assessment and monitoring of oxygen levels during exercise. It can provide real-time measures of oxygen saturation levels in the blood, allowing healthcare professionals and sport scientists to gauge how effectively the body is delivering oxygen to tissues during physical activity.

Similarly, pulse oximetry can assist in identify any potential oxygen delivery limitations, resulting in hypoxia, where there's inadequate oxygen supply to body tissues. This is especially pertinent during intense exercise and at high altitudes, where oxygen levels might be lower. By continuously monitoring oxygen saturation, athletes can be alerted to instances of hypoxia, enabling prompt adjustments to their exercise intensity or environment to ensure safety and performance optimization.

Pulse oximetry also aids in assessing training adaptations and optimizing workout routines. By tracking oxygen saturation levels during various training phases, athletes and coaches can gain insights into how efficiently the body is utilizing oxygen. This data helps fine-tune training programs and understand the body's response to different workout loads, ensuring that training regimens are tailored to individual needs for optimal performance gains.

Lastly, pulse oximetry plays a role in overall health monitoring and safety precautions. Consistently low oxygen saturation levels during exercise could indicate underlying health issues, particularly respiratory or cardiovascular problems. By regularly monitoring these levels, athletes can identify potential health risks and take appropriate measures to address them.

Pulse Oximetry Validation

There are many different models of pulse oximeters available, and many of these have been validated. The Ohmeda/Biox models are the most popular, and have therefore been mostly studied.

Every model of pulse oximeter is potentially different in its accuracy. Although based on the same measurement principle, the algorithm used for calculation of SaO2 may vary. Also, wear and tear on the sensor probe may effect the light emitter and sensor. Therefore every individual machine is required to be validated.

There have been many studies which have conducted comparisons of SaO2 measurement by a pulse oximeter to CO-oximeter measurements of arterial blood, however, comparing the results of these becomes difficult due to differences in protocols. Such differences include subject copulation and size, whether exercise is involved, sensor sites, pulse oximeter averaging periods, and the range of O2 saturations over which the comparisons are made.

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The above information is presented as a general guide. The author and publisher take no responsibility for any possible consequences of any treatment, procedure, exercise, action or application of medication based on this information. See more: Disclaimer.

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