An oximeter measures the oxygen level in your blood. This is useful for avid athletes, smokers, or people with heart problems. This way, you can see at a glance whether the oxygen is properly distributing through your body and whether there is any oxygen deficiency. An oximeter also measures your heart rate, which tells you a lot about the health of your heart. An oximeter is compact and easy to carry with you. As soon as you feel less well, you perform a saturation measurement to see if the oxygen level in your blood is correct and whether your heart rate is good.