I've noticed that a pulse oximeter at my fingertip lags my breathing effort by a noticable amount. I conclude that it takes some time for freshly oxygenated blood to travel from the lungs to the fingertips.
What lag time should I expect? Is there a chart or study which provides an estimate based on heart rate?
Is the lag greater for fingers, or toes? Presumably toes, being further from the heart and lungs, but perhaps the circulatory system has a larger carrying capacity and evens it out for the legs and feet.