Watch the SaO² (Oxygen Saturation) of your blood change with breath holding exercises to simulate High Altitude training.
In the sports world it is now believed that it is best to live high and train low so that we may acclimatize to compete at altitude whilst gaining maximum benefit of both. This is of course not terribly practical unless we worked and lived on a high mountain next to the sea and that we could move easily between the two so that we were able to do this. Simulating high altitude at sea levels has an added benefit of utilizing the Oxygen present to be able to train at maximum effort.
Many athletes travel with the Oxygen tents or train with masks to simulate the effect of high altitude. The air at altitude has a lower O² pressure (PO²) and this means that less O² is available from the air we breathe in during exercise. When moving from low altitude to high altitude we have a period of acclimatisation so that the O² saturation in our blood normalises. O² Saturation is the % of haemoglobin molecules carrying O². The Hematocrit (red blood cells or haemoglobin) increases to enable the blood to carry more oxygen. The normal Oxygen Saturation (Sao2) as seen on the pulse oximeter in the picture below is between 95-99% at sea level and once acclimatised at a higher altitude. It will appear lower than normal when you first arrive at high altitude. 100% is not achievable unless there is no transfer of O² from the blood into the tissue. It takes 2-3 weeks to fully acclimatize to 2000m if you wish to compete effectively at that altitude in an endurance event.
So how do we simulate high altitude training at sea level? The breath holding exercises in the Oxygen Advantage program can be practised during low and high intensity training at sea level to drive down the SaO² levels which in effect is what happens when you train at altitude. The body adjusts to the lack of O² and the kidneys release natural erythropoietin (EPO) signalling to the body that it needs more red blood cells to deal with the lack of O². The spleen or blood bank also releases more red blood cells helping the body to adapt. The more red blood cells (haemoglobin) the higher the O² carrying capacity of the blood and the easier it is to perform better at high and low altitudes.
There is more to this however. The O² must also transfer easily to the tissue from the red blood cells. If the bond between Haemoglobin and the O² molecule is too strong, then the O² will not transfer easily into the cells where it is required. This is another topic around CO² tolerance.
The Video shows how during a breath hold exercise, the saturation is driven down. It is a delayed effect after a breath hold exercise and once breathing has been resumed.