Pulse oximetry provides a measure of the percentage of oxygen in the blood. The usual range of readings on pulse oximetry is 97-99%. Older people may have lower pulse oximetry readings than younger people, and young women have higher readings than young men. People with dysphagia have been shown to have lower pulse oximetry readings during swallowing, thus this tool is now used to aid identification of dysphagia. However, others have indicated that lower levels may not be a sign of aspiration, and researchers have recommended caution in using this tool in swallow assessments. Overall, there is a lack of evidence exploring pulse oximetry levels during normal swallowing. Thus, the purpose of this study was to examine pulse oximetry levels in healthy participants across a variety of bolus consistencies and in people with COPD. Sixty healthy young men and women between the ages of 18 and 38, and 60 healthy older men and women aged 60 years and over, participated in the experiment. Eleven participants with COPD also participated. Pulse oximetry measures were recorded for participants whilst drinking thin fluids, eating applesauce and eating a piece of fruit. For all healthy subjects and those with COPD, there was no difference in pulse oximetry when eating and drinking or at rest, nor between bolus types. There were only small differences across age and gender, with younger people having a higher pulse oximetry than older, and women higher than men. This data is useful for speech and language therapists who have used pulse oximetry as a measure of swallow function, but indicate further research is required for reliable use of this as a true reflection of swallowing difficulties.