healthy male with decreased 02 sats

Im a 29 year old male in decent physical condition. Hypertensive at times, cholesterol normal. I work out with weights 3 times a week and try to do some form of cardio 1-2 times a week. Im a medical assistant and where i work i will check my o2 sats and i can never seem to get mine over 97% on room air. I know this is considered normal, but for my age ,activity level and no respiratory disorder why is mine not higher. I check patients everyday that have mulitple respiratory problems, older, copd, asthma, chronic smokers and they wil have 02 sats higher than mine. At rest mine is usually arounfd 95-96% while most of my chronic respiratory patients or chropnic smokers will have sats in the 99-100% on room air. Ive never smoked and noticed in the last year i have decreased aerobic capacity. I get winded a lot with milder exertion than i used to with a feeling lke i cant inhale deeply. Ive even been using an inspirometer at home but it doesnt seem to help. Any advice.

[National Jewish Health]

What you describe is most likely simply, an instance of biologic variability, related not only to your lungs but also to the oxygen binding characteristics of your hemoglobin. It is probably of no physiological significance.   However, given your perceived reduction in aerobic capacity along with the dyspnea ("with milder exertion"), it is conceivable that these could be early signs of a cardiac or pulmonary disorder or even a sign of occult anemia.  This could be, at least in part, a reflection of anxiety about your oxygen level.

You would do well to have a Chest X-ray, PFT's, Lung and Heart exam and a CBC.  The other possibility is that you might have a small percentage of an abnormal Hemoglobin, such as Methemoglobin, with less than normal oxygen affinity. Methemoglobinemia can be congenital and acquired.  When present in low concentrations, oximetry will show varying degrees of desaturation. If you are anemic, you should have hemoglobin electrophoresis, along with glucose-6-phosphate hydrogenase activity.