Adenosine triphosphate (ATP) is the biochemical way to store and use energy. F or your muscles -- in fact, for every cell in your body -- the source of energy that keeps everything going is called ATP.
An approximate blood oxygen level can also be estimated using a pulse oximeter â a small device that clips on your finger. Though the pulse oximeter actually measures the saturation of oxygen in your blood, the results are often used as an estimate of blood oxygen levels.Normal pulse oximeter readings range from 95 to 100 percent, under most circumstances. Values under 90 percent are considered low.1  Causes.n approximate blood oxygen level can also be estimated using a pulse oximeter â a small device that clips on your finger. Though the pulse oximeter actually measures the saturation of oxygen in your blood, the results are often used as an estimate of blood oxygen levels.
What does a pulse oximeter measure? 1  The oxygen saturation of haemoglobin in arterial blood-which is a measure of the average amount of oxygen bound to each haemoglobin molecule. 2  The pulse rate-in beats per minute, averaged over 5 to 20 seconds. The oxygen saturation of haemoglobin in arterial blood-which is a measure of the average amount of oxygen bound to each haemoglobin molecule. 2  The percentage saturation is given as a digital readout. 3  The pulse rate-in beats per minute, averaged over 5 to 20 seconds.