When we are talking of exercise and rest like sleep we can see that there is a difference not only in the breathing rate but also heart rate. When we are exercising the Oxygen demand by the muscles increases, in consequence, blood circulation increases as well as Oxygen intake by the lungs, there is an increase in oxygen diffusion from oxygen to blood and carbon dioxide from the blood to alveoli. There is an opening of capillaries that were closed at rest and greater dilation of those that were already open. Meanwhile, when we are sleeping we are at rest, in this case, the muscles do not require large quantities of oxygen, in the same way, the heart rate does not increase, in consequence, there is no increase in oxygen diffusion. In the same way, depending on the considered sleep state, when is very deep the respiratory rate diminishes even more.